Field

[0001 ] The present disclosure relates to building components such as building blocks, and more particularly to building blocks for use in toys or industry that are modular, inter-connectible, and/or stackable.

Background

[0002] Building blocks are widely used in the construction of structures including buildings, figures and apparatus, as toys, stationary or in industry. Building blocks which are modular, inter- connectible, and/or stackable can be used as components to create structures of many types of structures of many different shapes and configurations. Inter-connectible building blocks comprising built-in connection members are advantageous to facilitate expeditious, efficient and convenient interconnection of adjacent blocks to facilitate construction with less time and less manual work.

Disclosure

[0003] A building block disclosed herein comprises at least one rigid panel member on which at least one connection member is integrally formed and on which an intermediate aperture associated with the connection member is defined. The connection member may be configured for entering into mated mechanical coupled engagement with a counterpart connection member when the building block and the counterpart connection member are moved relatively towards each other along a coupling direction, the coupling direction being orthogonal to a base surface of said panel member. The connection member may comprise a hollow shell member which extends in the coupling direction and spans transversely across said intermediate aperture, the coupling direction being orthogonal to a base surface of said panel member from which the hollow shell member projects. The hollow shell member may comprise a transversely extending arcuate end cap portion and an intermediate shell portion, the intermediate shell portion surrounding said intermediate aperture, being in abutment with both the end cap portion and the panel member and connecting the end cap portion to the panel member. A plurality of connection members may be formed on the panel member, a matrix of arcuate bridging portions formed by the hollow shell members of plurality of connection members is integrally formed on the panel member. [0004] The connection member may be a snap connector and the hollow shell member defines a hollow bulging snap-fit portion of the snap connector, the bulging snap-fit portion being adapted for making snap-fit engagement with a counterpart snap connector having opposite, matched and complementary mating feature. The snap connector may be a male-type connector having a ball- shaped head or a female-type connector having a connector receptacle or ball-joint socket for receiving a ball-joint or a ball shaped connector head.

[0005] The intermediate aperture may be defined by an internal peripheral wall on the panel member, and the hollow shell member cooperates with the internal peripheral wall of the panel member to form a connector receptacle. The internal peripheral wall may also define a collar portion and an entry compartment to the connector receptacle.

[0006] The internal peripheral wall of the panel member may tapers or converges to narrow on extending away from the end cap portion of the hollow shell member may to defined a tapered or converging collar portion and a tapered or converging collar portion entry compartment, the collar portion and the entry compartment tapering or converging to narrow on approaching an entry end of said connector receptacle to facilitate snap-fit reception of an engaging portion of a counterpart snap connector.

[0007] The collar portion may be defined by a collar member, the collar member projecting from a base on the panel member and extending in an axial direction away from the base, the axial direction being parallel to the coupling direction. A peripheral groove or a peripheral channel may be formed on the panel and surrounding the collar member to permit resilient transversal deflection of the collar member into the groove or channel upon encountering a bulging snap-fit engaging portion of a counterpart snap connector on transiting into or out of the connector receptacle. The bulging snap-fit engaging portion may have a periphery which is curved or follows the curvature of a defining sphere.

[0008] The building block may comprise a plurality of panel members and a block peripheral wall interconnecting the panel members. The plurality of rigid panel members may consist of a first panel member and a second panel member and the first and second panels members cooperate to define a hollow block internal compartment. A plurality of connection members may be formed on the first panel member, on the second panel member, or on both the first panel member and the second panel member.

[0009] A plurality of connection members may be formed on the first panel member, and the plurality of connection members comprises at least one connection member of a first type and at least one connection member of a second type. A connection member of the first type and a connection member of the first type may be connection members having opposite and complementary mating properties and/or opposite or complementary mechanical mating features. [0010] At least one connection member pair or a plurality of connection member pairs may be formed on the panel member. Each connection member pair may comprise one connection member of a first type and one connection member of a second type which are axially aligned and share a common centreline. A connection member of the first type and a connection member of the first type may be connection members having opposite and complementary mating properties and/or opposite or complementary mechanical mating features. A connection member of the first type may comprise a protrusion member having a protruding engaging portion which is defined by the hollow shell member, and a connector of the second type comprises a connector receptacle having receptacle compartment which is defined by a peripheral wall. The internal cavity of the hollow shell member and the receptacle compartment of the connector receptacle may be in communication through said intermediate aperture.

[001 1 ] An aggregate of building blocks comprising a first building block and a second building block. Each building block a first panel member on which a first plurality of connection members may be formed, a second panel member on which a second plurality of connection members is formed, and a peripheral panel member interconnecting the first panel member and the second panel member to define an internal compartment of the building block. The connection member may be configured for entering into mated mechanical coupled engagement along a coupling direction with a counterpart connection member, the coupling direction being orthogonal to a base surface of said panel member. At least one of said connection member of the first type or said connection member of the second type may has a hollow shell member, the hollow shell member defining an engagement portion of the connection member and having an intermediate aperture on the panel member on which the connection member is formed. The hollow shell member may extend in the coupling direction and spans transversely across said intermediate aperture, the coupling direction being orthogonal to a base surface of said panel member from which the hollow shell member projects. The hollow shell member may comprise a transversely extending arcuate end cap portion and an intermediate shell portion, the intermediate shell portion surrounding said intermediate aperture, being in abutment with both the end cap portion and the panel member and connecting the end cap portion to the panel member.

[0012] A groove, channel, undercut, or depressed region herein may extend along a circular or helical path.

[0013] In some embodiments, the connection member is circularly symmetrical about the centerline of the connector and has a circular outer profile at different axial levels. In some embodiments, the connection member is substantially circularly symmetrical but has a non- circular outer profile at different axial levels. The non-circular outer profile may be in a polygonal shape, for example, regular polygonal shapes, having 4 or more sides, including, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, etc., and the polygon defining the polygonal shape is preferably a regular polygon having sides of equal widths. In some embodiments, the connection member has a non-circular outer profile at different axial levels

[0014] A building block comprising a base portion, a first coupling portion comprising at least one first connection member projecting from a first surface on a first side of the base portion and extending in a first axial direction, and a second coupling portion comprising at least one second connection member on a second surface on a second side of the base portion and extending in a second axial direction is disclosed. The first connection member comprises a head portion and a first coupling region which interconnects the head portion and the first surface. The second connection member comprises a receptacle region and a second coupling region, the second coupling region extending in a second axial direction to define a retention region and an entry aperture into the receptacle region and the receptacle region comprising a receptacle wall defining a receptacle compartment. The first coupling region comprises a first type of coupling arrangement having a first coupling characteristic and the second coupling region comprises a second type of coupling arrangement having a second coupling characteristic, the second coupling characteristic being opposite or complementary to the first coupling characteristic.

[0015] In some embodiments, the first coupling region comprises an engagement portion which is formed as an undercut, a channel or a depressed region on the first connection member, for example, a circumferentially or radially extending undercut, a channel or a depressed region, and the second coupling region comprises a retention device which extends radially inwards from an outside surface to define a minimum transversal entry aperture into the receptacle region, the minimum entry aperture being smaller than the maximum transversal clearance of the receptacle region.

[0016] In some embodiments, the first coupling region comprises an engagement portion which is formed as a radial or circumferential protrusion, a collar portion or a lip portion projecting radially from a main body of the first connection member defining the neck portion, and the second coupling region comprises a retention device which extends radially inwards from an outside surface to define a minimum transversal entry aperture into the receptacle region, the minimum entry aperture being smaller than the maximum transversal clearance of the receptacle region. The undercut, a channel or a depressed region may extend along a helical path or a circular path, whether continuous, intermittent or broken. [0017] The engagement region and the corresponding or counterpart retention device may extend along a helical path or a circular path, whether continuous, intermittent or broken.

[0018] An aggregate or an assembly of building blocks comprising a first building block and a second building block is disclosed. Each one of the first building block and the second building block comprises a base portion. The first building block comprises a first coupling portion comprising at least one first connection member projecting from a first surface on a first side of the base portion and extending in a first axial direction. The second building block comprises a second coupling portion comprising at least one second connection member on a second surface on a second side of the base portion and extending in a second axial direction. The first connection member comprises a head portion and a first coupling region which interconnects the head portion and the first surface. The second connection member comprises a receptacle region and a second coupling region, the second coupling region extending in a second axial direction to define a retention region and an entry aperture into the receptacle region and the receptacle region comprising a receptacle wall defining a receptacle compartment. The first coupling region comprises a first type of coupling arrangement having a first coupling characteristic and the second coupling region comprises a second type of coupling arrangement having a second coupling characteristic, the second coupling characteristic being opposite or complementary to the first coupling characteristic.

[0019] The first connection member and the second connection member are complementary connection parts or connection counterparts which are to cooperate to function as a connection mechanism. In use, the head portion of the first connection member is to move into the receptacle or receptacle region of the second connection member along an axial direction upon overcoming an entry resistance of the second connection member. The head is retained inside the receptacle or receptacle region after entry into the receptacle or receptacle region and is movable out of the receptacle or receptacle region upon overcoming an exit resistance of the second connection member.

[0020] The entry resistance and the exit resistance is due to cooperative interaction between radially extending portions of the first coupling region and the second coupling region. The radially extending portions are semi-rigid and resilient and are deformable to permit entry and exit of the head portion.

[0021 ] In some embodiments, the second coupling region comprises a collar portion which projects radially inwards, and the extend of inward protrusion is to obstruct axial movement of the head portion into or out of the receptacle region, but the obstruction is overcome by exerting a sufficient axial force to cause resilient deformation of the collar portion and/or the head portion.

[0022] The first connection member and the second connection member may be used as connection parts or connection counterparts separable from the building blocks, that is as standalone connection parts or attached to other building components.

[0023] In some embodiments, the first coupling member comprises a coupling head portion and a neck portion. The coupling head is spaced apart from the first surface and has a maximum lateral extent. The neck portion interconnects the head portion and the first surface and defines an engagement region. The second coupling member comprises a receptacle which projects into the base portion to define a receptacle compartment and a retention region defining a collar portion which projects away from the receptacle and the base portion and defines a minimum entry clearance. The maximum lateral extent is larger than the minimum lateral clearance.

[0024] There is also disclosed a building block comprising a base portion and a plurality of first connection members projecting from a first surface on a first side of the base portion. The first connection member extends in a first axial direction and comprises a head portion and an indented coupling portion (or neck portion). The indented coupling portion may be in abutment with the first surface and being intermediate the head portion and the first surface. The oppositely facing indented coupling portions of the plurality of first connection members cooperate with the first surface to define a receptacle for latched reception of a connection base of a connection member. The connection base has a transversal extent larger than the transversal or lateral clearance defined between and among the head portions of the plurality of first connection members. The connection base may have a circular or a substantially circular outline. The head portion may taper to narrow as it extends towards the first surface to define the indented coupling portion. The indented portion may be formed as a channel, for example, a flat bottomed channel, a v-shaped channel, a round-bottomed channel.

Figures

[0025] The present disclosure will be described by way of example and with reference to the accompanying figures, in which:

Figure 1 A is a top perspective view of an example building block, Figure 1 B is a bottom perspective view of the building block of Figure 1 A, Figure 1 C is a side elevation view of the building block of Figure 1 A, Figure 1 D is a cross-sectional view taken along line X-X' of Figure 1 A and axially, Figure 1 E is a locally enlarged view of a first portion of Figure 1 D, Figure 1 F is a locally enlarged view of a second portion of Figure 1 D,

Figure 1 A1 is a cross-sectional view of an example assembly of building blocks formed from stacked engagement of a plurality of the building blocks of Figure 1 A,

Figure 1 A2 is a locally enlarged view of a connected portion of Figure 1 A1 ,

Figure 2A is a top perspective view of an example building block according to the disclosure,

Figure 2B is a bottom perspective view of the example building block of Figure 2A,

Figures 2C and 2D are respectively, plan view from above and below of the example building block of Figure 2A,

Figure 2E is a side elevation view of the example building block of Figure 2A,

Figure 2F is a cross-sectional view of the example building block of Figure 2A,

Figures 2A1 and 2A2 are respectively, a perspective view and front plan view of two example building block of Figure 2A in a stack arrangement,

Figure 3A is a top perspective view of an example building block according to the disclosure,

Figure 3B is a bottom perspective view of the example building block of Figure 3A,

Figure 3C is a cross-sectional view of the example building block of Figure 3A,

Figure 3D is a cross-sectional view showing an enlarged portion of the example building block of Figure 3A,

Figure 4A is a top perspective view of an example building block according to the disclosure, Figure 4B is a top plan view of the example building block of Figure 4A,

Figure 4C is a cross-sectional view of the example building block of Figure 4A, and

Figures 5A and 5B are perspective views of an example building block according to the disclosure. Description

[0026] Referring to Figures 1 A, 1 B and 1 C, an example building block 100 comprises a first surface defining member 120, a second surface defining member 140 and a block peripheral member 160 which cooperate to define a main block body 180. A plurality of first connection members 122 is formed on the first surface defining member 120 to collectively define a first coupling portion, a plurality of second connection members 142 is formed on the second surface defining member 140 to collectively define a second coupling portion, and the block peripheral member 160 defines a lateral peripheral wall of the building block 100. [0027] The first connection member 122 is configured for making coupled engagement with a counterpart and matched connection member and is to enter into the coupled engagement in a first coupling direction. The second connection member 142 is configured for making coupled engagement with a counterpart and matched connection member and is to enter into the coupled engagement in a second coupling direction. [0028] The main body 180 is a shell-like structure comprising a hollow body which defines a hollow internal block compartment 190, as depicted in Figure 1 D. Each of the first surface defining member 120, the second surface defining member 140 and the block peripheral member 160 is a sheet-like member ( or "sheet member" in short) or a plate-like member (or "plate member" in short) having a thickness which is substantially smaller than the thickness of the building block, the thickness of the building block being measured in a direction orthogonal to the line X-X' of Figure 1 between the outward facing surface 1201 (or the upward facing surface in the normal orientation of Figure 1 D) of the first surface defining member 120 and the outward facing surface 1401 (or the downward facing surface in the normal orientation of Figure 1 D) of the second surface defining member 140. [0029] The hollow internal block compartment 190 defines an internal cavity which extends axially between the first surface defining member 120 and the second surface defining member 140 and delimited laterally by the block peripheral member 160. Axial clearance of the internal cavity, as defined by the axial separation distance between the inward facing surface 1202 (downward facing in the normal orientation of Figure 1 D) of the first surface defining member 120 and the inward facing surface 1402 (or upward facing in the normal orientation of Figure 1 D) of the second surface defining member 140, is substantially larger than the sheet thickness or plate thickness of the individual surface defining members 120, 140 and/or the block peripheral member 160. The axial clearance of the internal cavity is substantially equal to the height of the block peripheral member 160 minus the aggregated thickness of the first surface defining member 120 and the second surface defining member 140. The height of the block peripheral member 160 is defined in an axial direction A-A', B-B' which is orthogonal to the first surface defining member 120 and/or the second surface defining member 140 and the thickness of the block peripheral member 160 is measured in a transverse direction which is orthogonal to the axial direction. A surface defining member 120, 140 is also referred to as a panel member or a surface bearing member herein, since it also defines the inward/outward or the upward/downward facing surfaces.

[0030] The connection member 122, 142 comprises a hollow shell body as an example of a shelllike structure. The hollow shell body is defined by a rigid shell member which projects axially from the surface defining member 120, 140 and extends in both the axial and transverse directions to define a rigid structure. The hollow shell body defines a connector main body, a connector internal cavity and a hollow connector compartment inside the connector main body. The hollow shell body is defined by a sheet-like member or a plate-like member shell member. A sheet-like member or the plate-like member herein has a first surface and a second surface. The first surface and the surface are parallel and thickness of the shell member is defined by the separation distance, that is orthogonal distance, between the first surface and the surface. For the example first connection member 122, the first surface is an outer peripheral surface of the connection member 122 defining the outer profile of the connection member 122, and the second surface is an inner peripheral surface of the connection member 122 defining the internal profile of the connection member 122 or boundary of the connector internal cavity. For the example connection member 122, 142 the first surface is an outer peripheral surface of the connection member 122, 142 defining the outer profile of the connection member 122, 142, and the second surface is an inner peripheral surface of the connection member 122, 142 defining the shape or boundary of the connector internal cavity. The internal cavity of the first connection member 122, which is inside and defined by the shell body of the first connection member 122, is in communication with the internal cavity of the internal block compartment 190 and the communication is facilitated by means of a through aperture formed on the first surface defining member 120. The portion of the first surface defining member 120 which defines the through aperture also defines a through passageway, through which the internal cavity inside the connection member 122 and the internal block compartment 190 are in communication. This through aperture, which is formed on the first surface defining member 120, is an intermediate aperture which interconnects the internal block compartment 190 and the internal cavity inside the first connection member 122.

[0031 ] The internal cavity of the second connection member 142, which is inside and defined by the shell body of the second connection member 142, is open to the outside (that is, exterior to the main body 180) by means of a through aperture which is formed on the second surface defining member 140. The portion of the second surface defining member 140 which defines the through aperture also defines a through passageway through which an external protrusion member can move into the internal cavity and then received or retained by the internal cavity. This through aperture, which is formed on the second surface defining member 140, is an intermediate aperture which interconnects the internal cavity of the second connection member 142 and the exterior.

[0032] The hollow shell body of the connection member 122, 142 is integrally formed on or with the surface defining member 120, 140 and the hollow shell body joins the surface defining member 120, 140 at the periphery of the intermediate aperture so that the inner peripheral surface of the hollow shell body is a smooth continuation from the inner peripheral surface defining the intermediate aperture, for example, with seamless or non-salient transition between the surfaces.

[0033] The first connection members 122 are integrally formed on or integrally formed with the first surface defining member 120 and the second connection members 142 are integrally formed on or integrally formed with the second surface defining member 140.

[0034] Where there is a plurality of connection members formed on a surface defining member 120, 140, a corresponding plurality of associated intermediate apertures is also defined on the surface defining member 120, 140 [0035] In some embodiments, the first connection members 122, the first surface defining member 120 and the block peripheral member 160 are integrally formed as a single first integral piece; the second connection members 142 and the second surface defining member 140 are integrally formed as a single second integral piece; and the building block is formed by joining the first and second integral pieces together. More specifically, the second integral piece is joined to the bottom end of the block peripheral member 160 which is an axial end of the block peripheral member 160 most distal to the first surface defining member 120.

[0036] In some embodiments, the first connection members 122 and the first surface defining member 120 are integrally formed as a single first integral piece; the second connection members 142, the second surface defining member 140 and the block peripheral member 160 are integrally formed as a single second integral piece; and the building block is formed by joining the first and second integral pieces together. More specifically, by joining the first integral piece to the top end of the block peripheral member 160 which is an axial end of the block peripheral member 160 most distal to the second surface defining member 140.

[0037] In example embodiments, the components of the building block are made of structural materials such as hard and/or rigid plastics, for example, ABS (acrylonitrile butadiene styrene) or PC (polycarbonate), or metal for use in structures such as steel, aluminum or aluminum alloys and are joined by gluing, welding or other appropriate known joining methods available.

[0038] The first surface defining member 120 and the second surface defining member 140 are rigid panel members which are parallel and are spaced apart, separated by the internal cavity of the internal block compartment (or "compartment internal cavity"). The first coupling direction and the second coupling direction are parallel to the axial direction and the axial centerlines of the connection members are parallel. The axial centerline of a connection member herein is a centerline about which the connection member is laterally or circularly symmetrical.

[0039] An example plurality of four first connection members 122 is formed on the first surface defining member 120 and an example plurality of four second connection members 142 is formed on the second surface defining member 140. The connection members 122, 142 are distributed in a regular matrix such that the separation distance between adjacent connection members along a row or along a column on the same surface defining member is the same. The separation distance between adjacent connection members is conveniently taken as the distance between the axial centerlines of the adjacent connection members for sake of simplicity.

[0040] The connection members 122, 142 on the first surface defining members 120 and the second surface defining member 140 are centerline aligned such that for a first connection member 122 on the first surface defining member 120 there is a corresponding centerline aligned second connection member 142 on the second surface defining member 140. [0041 ] In the example building block of Figure 1 A, the connection members 122 on the first surface defining member 120 are connection members of a first type and the connection members 142 on the second surface defining member 140 are connection member of a second type. A connection member of the first type herein is also referred to as a male-type or a protrusion-type connection member, and a connection member of the second type herein is also referred a female-type or a receptacle-type connection member. A connection member of the first type has opposite mechanical mating properties to a connection member of a second type.

[0042] The example first connection member 122 and the example second connection member 142 are matched and compatible connection members. A pair of matched and compatible connection members is one which comprises component connection members and the component connection members have mechanical mating features which are opposite, complementary and dimensions matched. The component connection members, when formed on separate carriers, are to enter into coupled engagement (which means coupled mechanical engagement, snap engagement, or snap latching) when the component connection members are relatively moved along a coupling direction and pressed together.

[0043] The hollow shell body of the first connection member 122 projects axially away from the main body 180 (and away from the second surface defining member 140) and the centerline of the first connection member 122 is orthogonal to the outward or upward facing surface 1201 of the first surface defining member 120. The hollow shell body of the second connection member 142 projects axially away from the second surface defining member 140 and projects into the internal block compartment 190, and the centerline of the second connection member 142 is orthogonal to the outward or downward facing surface 1401 of the second surface defining member 140.

[0044] The hollow shell member of a connection member 122, 142 has an arcuate or curved cross sectional profile and the rigid shell spans or extends across the through aperture on the surface defining member 120, 140. An arcuate or curve shaped shell member which spans or extends across the bridging apertures forms a spanning structure which provides structural reinforcement or supplemental structural reinforcement to compensate for structural weakness on the surface defining member 120, 140 due to formation of the bridging apertures thereon.

[0045] In example embodiments, the hollow shell member is arc-shaped, arch-shaped, dome- shaped, cap-shaped, egg shell shaped, or has an arc-shaped, arch-shaped, dome-shaped, cap- shaped, and/or egg-shell shaped top or top structure, and the arcuate or curved upper or top portions of the hollow shell member extends radially, in more than one transverse directions or a plurality of transverse directions orthogonal to the axial direction, and spans across the intermediate aperture as a spanning structure. A shell-like spanning structure having an arc- shaped or arch-shaped cap-shaped top or top structure which spans across an intermediate aperture on the surface defining member 120, 140 provides structural reinforcement to the surface defining member 120, 140 in the direction of extension of the arc or arch. A shell-like structure having a dome-shaped, cap-shaped, or egg-shell-shaped top structure when spanning across an intermediate aperture on the surface defining member 120, 140 provides radial or multi-directional structural reinforcement to the surface defining member 120, 140 in the directions of extension of the dome, cap, or egg-shell. In such embodiments, the connection member provides structure reinforcement to the associated surface defining member 120, 140 while at the same time defining a connection member and its associated features such as the internal cavity and the bridging aperture. [0046] The shell-like structure or the hollow shell member may be in the form of a continuous smooth shell, a gridded or textured shell, or in the form of a grid-like structure, a net-like structure, a grille-like structure, or a web-like structure without loss of generality.

[0047] In some embodiments, including the example of Figures 1 A to 1 D, the hollow shell member comprises an upper portion (or first portion) defining an end cap at the axial free end of the hollow shell member and a lower portion (or second portion) which extends between the end cap and lower surface, that is the downward facing surface 1401 of the surface defining member.

[0048] In some embodiments, a through aperture may be formed on the end cap or the center of the hollow shell member, the center being where the centerline of the hollow shell member passes. [0049] In some embodiments, such as the example embodiment of Figure 1 A, the hollow shell member of the first connection member 122 defines a protrusion member which is closely matched with a receptacle defined by the hollow shell member of the second connection member 142.

[0050] The connection member 122, 142 projects above the base surface defining member 120, 140 by an axial height which is substantially larger than the thickness of the base surface defining member 120, 140. In example embodiments, the axial height is 3 to 10 times or more (including 3, 4, 5, 6, 7, 8, 9, 10, or any range or ranges formed by combination of the aforesaid values) the thickness of the base surface defining member 120, 140. A base surface defining member 120, 140 herein means the surface defining member 120, 140 from which a surface of which the connection member 122, 142 projects or extends. In example embodiments for tor application as toy building blocks, the thickness of the surface defining member 120, 140 or the block peripheral wall 160 may be in the region of 0.5mm to 2mm, (including 0.5, 0.6, 0.7, 0.8, 0.9, 1 .0. 1 .1 , 1 .2, 1 .3, 1 .4, 1 .5, 1 .6, 1 .7, 1 .8, 1 .9, 2.0, or any range or ranges formed by combination of the aforesaid values). In other applications, such as industrial applications, the thickness would be substantially higher, for example, 3 to10 times of that for toy applications (including 3, 4, 5, 6, 7, 8, 9, 10, or any range or ranges formed by combination of the aforesaid values) to provide sufficient structural strength and rigidity as required or appropriate.

[0051 ] In the example of Figure 1 A, the four example connection members 122, 142 are distributed in a square matrix of two rows by two columns, each of the surface defining members 120, 140 is substantially square, and the block peripheral member extends in an axial direction to interconnect the first and second surface defining members 120, 140, and extends transversely to surround the first and second surface defining members 120, 140. [0052] The connection members may be distributed in any desirable order or configuration. In typical examples, the connection members are distributed in a matrix comprising N rows and M columns, N, M being an integer, where separation distance between adjacent rows and adjacent columns are equal and uniform. In some embodiments, the connection members are distributed in a circular matrix comprising N circular rows, where separation distance between adjacent rows and adjacent connection members are equal and uniform. For example, the connection members may be arranged in a square matrix of 3x3 (i.e., three rows and three columns), 4x4, 5x5, 6x6, etc.; rectangular matrixed of 2x3, 2x4, 2x5, 2x6, 3x4, 3x5, 3x6, 3x7, 4x5, 4x6, 4x7, circular matrixes of two, three, four, five etc. concentric rows (or rings) having uniform or non-uniform spacing.

[0053] In the example of Figure 2A, the four example connection members 222, 242 are distributed in a rectangular matrix of two rows by two columns, each of the surface defining members 220, 240 is substantially rectangular, and the block peripheral member extends in an axial direction to interconnect the first and second surface defining members 220, 240, and extends transversely to surround the first and second surface defining members 220, 240. In this example, the second connection member has an axial height which is comparable to half or more than ¼ of the height of the internal block compartment or the block peripheral wall 160.

[0054] In some embodiments, the spanning structure extends radially from the connection member and/or passes through the centerline of the connection member. [0055] In some embodiments, the spanning structure is laterally, circularly or radially symmetrical about the centerline of the connection member.

[0056] A connection member having a substantially hollow interior which is defined by a hollow shell member that spans across the bridging aperture as a spanning structure provides structural reinforcement to strengthen the surface defining member while also functioning as a connection member for making mechanical detachable engagement with a matched and complementary counterpart and possessing the benefits of light weight due to being hollow or being substantial hollow.

[0057] In some embodiments, the volume of the internal cavity of the connection member 122, 142 accounts for between 40% to 90% (including 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or less, or any range or ranges select from a combination of the aforesaid values or range or ranges) of the volume of the connection member. In other words, the connection member 122, 142 is between 40% to 90% hollow or unfilled.

[0058] The hollow shell member of a connection member 122, 142 comprises an internal peripheral wall and an external peripheral wall. The internal cavity of the connection member 122, 142 is defined by the internal peripheral wall of the hollow shell member.

[0059] In some embodiments, the internal peripheral wall of the hollow shell member has a dome- shaped, curved or arcuate downward facing ceiling portion to provide material effective structural strengthening, the ceiling being an inner facing surface of the end cap.

[0060] In some embodiments, the internal peripheral wall of the hollow shell member of a connection member defines a receptacle for closely fitted reception of a protrusion portion of a matched counterpart protrusion member of a counterpart connection member having a free or top axial end in the shape of a spherical cap or a spherical segment when the connection member and the counterpart connection member are in mechanical engagement, for example, in snap-fit engagement. When in said mechanical engagement, the downward facing curved or arcuate shaped ceiling portion of the hollow shell member will be in abutment contact and engagement with the upward facing surface of the free or top axial end of the corresponding or counterpart protrusion member. In preferred embodiments, the area in abutment contact would be at least 40% of the area of the curved or arcuate shaped ceiling portion, including more than 40%, 45% or more or less, 50% or more or less, 55% or more or less, 60% or more or less, 65% or more or less, 70% or more or less, 75% or more or less, 80% or more or less, 85% or more or less, 90% or more or less, 95% or more or less, 100% or less, or any range or ranges select from a combination of the aforesaid values or range or ranges).

[0061 ] In some embodiments, the portion of the internal peripheral wall of the hollow shell member which is in abutment with the portion of the surface defining member delimiting the bridging apertures extends in the axial direction to define a tubular portion.

[0062] In some embodiments, the shell forming the hollow shell member has a shell thickness which is comparable to, or smaller (for example slightly smaller) than the thickness of the surface defining member or the block peripheral member. In some embodiments, the shell thickness is substantially uniform. [0063] The surface defining member may have other shapes such as geometrical shapes, for example, circular, elliptical or polygonal, or non-geometric shapes without loss of generality. [0064] An example building block assembly 10 depicted in Figure 1 A1 comprises an aggregate of a first building block 100A and a second building blockl OOB in stacked engagement. Each of the building blocks 100A and 100B is identical to the building block 100 and the descriptions thereon are incorporated by reference for the benefit of succinctness with the same numerals applied with suffixes a or b optionally appended to correspond respectively with the building blocks 100A and 100B where appropriate.

[0065] The second building block 100B is stacked on the first building block 100A to form a stacked aggregate of connected or interconnected building blocks so that the first building block 100A and the second building block 100B are in a stack engaged configuration. When in this stacked engaged configuration, the first coupling portion which is defined by the ensemble of the first connection members 122A of the first building block 100A is in mechanical engagement with the second coupling portion which is defined by the ensemble of the second connection members 142B of the second building block 100B, and the downward facing surface of the second surface defining member 140B of the second the second building block 100B is in abutment contact with the upward facing surface of the first surface defining member 140A of the first building block 100A. When in this mechanical engagement relationship, the protrusion portions of the first connection members 122A which project above the first surface defining member are received in the receptacles which are defined by the corresponding second connection members 142B and are received in a closely fitted or interference fitted manner. [0066] As a hollow shell member of the first connection member 122A, 122B defines a protrusion member which is closely matched with a receptacle which is defined by the hollow shell member of the second connection member 142A, 142B, the protrusion member of the first connection member 122A on the first building block 100A is substantially wrapped around by the inside surface or the downward facing surface of the hollow shell member of the second connection member 142B of the second building block 100B when the protrusion member and the receptacle member are in mechanical engagement when in the mechanical engagement relationship.

[0067] More specifically, the downward facing surface and the laterally facing surface of the hollow shell body of the second connection member 142B of the second building block 100B is in abutment contact with the upward facing surface and the laterally facing surface of the hollow shell body of the first connection member 122A of the first building block 100A. In other words, the corresponding hollow shell members of the corresponding first and second connection member 122A, 142B are in closely fitted and stacked abutment contact when in this stack engaged configuration. As the corresponding hollow shell members of the corresponding first and second connection member 122A, 142B are arcuate and in closely fitted abutment contact, the mechanical engagement between the corresponding coupling portions provides supplemental structural reinforcement to the assembly as the two engaging hollow shell members would function as a stronger or double arcuate reinforcement structure. Connection member of the first type

[0068] An example connection member of the first type comprises a protrusion member 122 which projects away from a base surface and extends in an axial direction (A-A' of Figure 1 E) away from the base surface which is the upward facing surface 1201 of the first surface defining member 120 in this example. The protrusion member comprises a head portion 126 having a free axial end and a neck portion 128 which is intermediate the head portion 126 and the base surface 1201 . The neck portion 128 extends between the head portion 126 and the base surface 1201 and projects axially away from the base surface 1201 . The free axial end of the head portion 126 is a rounded end having a dome-shaped or arcuate top which is distal to the base surface 1201 and the head portion has a second end which is distal to the rounded end and proximal to the base surface 1201 and is in abutment connection with the neck portion 128. A connection member of the first type has male type mating features and properties and is also referred to herein as a "male type connector", a male type connector member or a male connector in short where the context requires or is appropriate.

[0069] In some embodiments, including that of Figure 1 A, the connection members are adapted for snap-fit engagement, so that a connection member of the first type is a male-type snap connector, a connection member of the second type is a female-type snap connector, and a pair of snap connectors comprising a male-type snap connector and a correspondingly shaped and sized matched female connector are in snap-fit engagement (or "coupled engagement") when the counterpart male and female connectors are snap-fitted together. [0070] The neck portion 128 of a male type snap connector diverges or flares to expand (at least initially) as it departs or projects axially away from an axial end which is in abutment with the base surface 1201 , and then joins the head portion at its distal axial end which is distal to the base surface 1201 . The neck portion 128 ceases to diverge and/or begins to taper or converge at its distal axial end meets or joins the head portion 126. A narrowed region is formed around the base of the neck portion which is immediately adjacent the base surface 1201 due to the initial divergence or flaring of the neck portion. The initial divergence or flaring of the neck portion can be viewed as a finishing convergence or tapering when progress is considered or viewed in the opposite axial direction. When so considered or viewed, the head portion tapers or converge gradually to narrow as it extends axially towards the base surface. The narrowed region defines a retention region which extends around the outer periphery of the base portion of the neck portion. The retention region is configured to cooperate with an anchoring device on a counterpart and matched connection member to form a coupled mechanical or anchored engagement. [0071 ] In some embodiments, including the example of Figure 1 A, the maximum transverse dimensions of the protrusion member occur at where the neck portion abuts the head portion. The head portion gradually converges or tapers to narrow as it extends away from the neck portion and the base surface until reaching its free axial end. The head portion may have a hemispherical shape as in this example, but may have a truncated end or may be in the form of a spherical frustum. The example head portion follows the surface curvature of a defining sphere and an example defining sphere is one which is defined by a circle having circular dimensions of the maximum transverse dimensions of the protrusion member. Where the head portion has a truncated end or frustum free end, the free axial end of the head portion may have a chamfered periphery so that a transversely extending a top shell portion of the hollow shell member is joined to an axially extending peripheral shell portion of the hollow shell member to provide more effective structural reinforcement in the transversal direction.

[0072] Referring to Figure 1 D, the protrusion member 122 comprises, on progressing along an axis of circular symmetry A-A', a base portion or a neck portion 128 having a base end which is proximal or in abutment with the base surface 1201 , a head portion 126 which is distal from the base surface 1201 defining a free end and a free end portion, and a middle portion which is intermediate the base surface 1201 and the head portion. The middle portion is a bulged junction portion where the maximum transversal dimensions of the protrusion member 122 occurs. The neck portion 128 tapers or converge to narrow as it extends towards its base end along the axis of circular symmetry and following a spherical curvature. The head portion tapers or converge to narrow as it extends from its free end towards the base end and the middle portion following a spherical curvature, which is the same spherical curvature as that of the neck portion.

[0073] In a different perspective, the neck portion flares or diverge to widen as it extends away from the base end along the axis of circular symmetry following a spherical curvature, and the head portion flares or diverge to widen as it extends towards the base end and the middle portion following the same spherical curvature.

[0074] In some embodiments, the protruding member has the shape of a spherical frustum and has a depth or height H in an axial direction, the axial direction being a direction extending along the axis of circular symmetry, and comprises a first spherical frustum having a depth hi , a second spherical frustum having a depth h2, and a middle plane defining the middle portion which is intermediate the first and second spherical frustum, where H=h1 +h2. Referring to Figures 1 A and 1 D, hi is the axial height of the head portion 126 and h2 is the axial height of the neck portion 128. In general, the value of hi and h2 can be between zero and R1 , where R1 is the radius of a circular plane at the maximum transversal span of the protrusion member. Where hi equals R1 , the head portion 126 is hemispherical, as in the case of Figure 1 A. Where h2 is zero, the height of the protruding member is equal to the height of the head portion.

[0075] In example embodiments, hi is in the region of 0%-100% of R1 , for example, 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% and/or any range or ranges selected from the aforesaid values, and the values of h2 are in the same or similar range but H must be smaller than D1 which is equal to 2R1 . For example, H may be in the region of 25-85% of D1 , for example, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, and/or any range or ranges selected from the aforesaid values. A preferred range of h2 is between 20%-40% for making effective snap-fit engagement with wedging.

[0076] The value of h2, which equals the axial extent of a neck portion, may be determined with reference to the strength rigidity and resilience of the materials of the protrusion member and/or the counterpart engagement member to be coupled with the protrusion member without loss of generality.

[0077] The protrusion member tapers to join the base surface at an acute angle to define a retention region at the base of the protrusion member. In some embodiments, the protrusion member curves convexly to converge towards the centerline and joins the base surface at an acute angle. [0078] In some embodiments, including the example of Figure 1 A, the protrusion member has a convexly curved base portion which is oppositely facing the base surface, and the convexly curved base portion of the protrusion member cooperates with the base surface to form a peripherally extending base wedging portion. The protrusion member curves convexly on projecting away from the base surface to cooperate with the base surface to define a tapered or narrowed retention region, the narrowed region is to function as a wedging portion for entering into wedging engagement with a corresponding anchoring portion of a counterpart and matched snap connector. The wedging portion progressively narrows, converges or tapers to narrow in a radial direction towards the centerline of the protrusion member as it extends in the axial direction towards the base surface. The axial end of the convexly curved portion which is proximal the base surface makes an acute angle with the base surface, in other word, it joins the base surface at an acute angle. [0079] The acute joining angle may be between 20 degrees to 85 degrees, for example, the joining angle may be 20 degrees or more, 25 degrees or more or less, 30 degrees or more or less, 35 degrees or more or less, 40 degrees or more or less, 45 degrees or more or less, 50 degrees or more or less, 55 degrees or more or less, 60 degrees or more or less, 65 degrees or more or less, 70 degrees or more or less, 75 degrees or more or less, 80 degrees or more or less, or 85 degrees or less, or a range defined by a combination of any of the aforesaid values and/or ranges. An example preferred range is 30 to 60 degrees. The joining angle is between 5 degrees to 70 degrees to the centerline, and the aforesaid angular values are each to be minus by 90 degrees if the joining angle is with reference to the centerline or axial line.

[0080] In some embodiments, the convexly curved base wedging portion extends from its base to reach a maximum transversal span at axial distance from the base, the transversal span being defined in a transversal direction which is orthogonal to the axial direction, and wherein the axial distance is ad1 % of a transversal width D1 at the maximum transversal span, ad1 being between 10% to 45% of D1 , including 10% or more, 15%or more or less, 20%or more or less, 25%or more or less, 30%or more or less, 35%or more or less, 40%or more or less, 45 % or less, or any range or ranges defined by any combination of the aforesaid values, range or ranges.

[0081 ] In some embodiments, the convexly curved based wedging portion extends from an initial transversal span at its base end to reach a maximum transversal span at an axial level from the base surface, the transversal span being defined in a transversal direction which is also the radial direction that is orthogonal to the axial direction. The initial transversal span is ts2% of the maximum transversal span D1 , and ts2 is between 55% to 95% of D1 , including 55% or more, 60% or more or less, 65% or more or less, 70% or more or less, 75% or more or less, 80% or more or less, 85% or more or less, 90% or more or less, 95% or less, or any range or ranges defined by any combination of the aforesaid values, range or ranges.

[0082] In some embodiments, the base of the convexly curved portion is on the base surface or at an axial distance from the base surface.

[0083] In some embodiments, the neck portion has the curved peripheral surface of a lower spherical segment of a sphere S having a spherical radius SR and an axial height of ah1 . A lower spherical segment herein being a spherical segment which extends for the axial height ah1 from a transversal plane of the sphere having a maximum transversal span, the axial height being measured in an axial direction parallel to the axis of circular symmetry of the spherical segment and the maximum transversal plane being a circular plane defined by SR. The transversal span of the neck portion, defined by a transversal plane which is orthogonal to the axial direction, progressively reduces on approaching the base surface so that the outer peripheral surface at or near the base end of the neck portion follows a convex curvature and forms an acute angle with the base surface, the base end of the neck portion being in abutment with on approaches the base surface. [0084] In some embodiments, the neck portion is a cylindrical body or a prismatic body which projects away from the base surface, and a tapered portion is formed at a peripheral region in abutment with or in proximity to the base surface. The tapered portion defines a peripheral depression or a peripheral recess which extends around the outer periphery of the neck portion and forms a retention groove or a retention channel as an example of a retention device or a wedging device. Where the tapered portion is in abutment with the base surface, the periphery of the neck portion defining the tapered portion defines the initial or narrowest transversal span of the neck portion on the base surface. Where the protrusion member is circularly symmetrical, the initial transversal span defines a circular plane which is orthogonal to the axial direction.

[0085] In some embodiments, the protrusion member defines a first circular plane which is parallel to the first surface and orthogonal to a center axis defined by the centerline at where the protrusion member meets the base surface and having a first radius r1 , the protrusion member flares outwardly as it projects axially away from the first surface and defines a second circular plane which is parallel to the first circular plane and at an axial height away from the first surface and having a second radius r2, the second radius being larger than the first radius and the first radius r1 is between 55% to 95% of SR, including 55% or more, 60% or more or less, 65% or more or less, 70% or more or less, 75% or more or less, 80% or more or less, 85% or more or less, 90% or more or less, 95% or less,, or any range or ranges defined by any combination of the aforesaid values, range or ranges .

[0086] The head portion continues from the neck portion and extends away from the neck portion in the axial direction and has the shape of a second spherical segment. The second spherical segment has an axial height ah2 which is defined between a second circular plane having a second radius r2 and a third circular plane which is axially spaced apart from the second circular plane and has a third radius r3, the third radius being smaller than the second radius r2. [0087] As the head portion extends axially away from the base surface or the neck portion, its transversal span gradually decreases and the rate of decrease gradually increases so that an outer side of the head portion is also convexly curved when viewed in the transversal direction. The head portion is laterally symmetrical about the centerline and, in some embodiments, the outside of the head portion follows the curvature of a sphere as it extends axially away from the neck portion. In a longitudinal cross-sectional view taken along the centerline, two mirror symmetrical arcuate portions are disposed on two diametrically opposite ends of the neck portion at the same axial level, as the head portion is laterally or circularly symmetrical about the centerline. Each of the convex sides has its convex surface facing away from the centerline or facing outwards.

[0088] In some embodiments, the head portion converges to a rounded end at its free axial end. The rounded end may be a spherical segment of a sphere.

[0089] In some embodiments, the second radius r2 is the radius of a sphere and the head portion follows the curvature of the sphere to converge to form a free rounded end. [0090] In some embodiments, the neck portion diverges in the transversal direction or flares as it extends axially away from the base surface until reaching a maximum transversal span at its axial end. The head portion then continues from the maximum transversal span at the axial end of the neck portion and tapers to converge at its axial free end as it extends in the axial direction.

[0091 ] A head portion which flares to expand its transversal span as it extends in an axial direction towards the base surface or towards the retention device facilitates easier or more convenient coupling insertion of a counterpart engagement device towards the retention device. A head portion that has a smaller transversal span at its axial free end would facilitate more convenient alignment with a retention or engagement device of a counterpart connection member.

[0092] A neck portion having a retention device which flares to expand its transversal span as it extends in an axial direction away from the base surface or towards the head portion facilitates more effective retention of a retention or engagement device of a counterpart connection member. The continuity in transversal span at the junction of the head and neck portion facilitates easy movement across the junction.

[0093] In some embodiments, the head portion is a spherical segment having a truncated free end. In some embodiments, the head portion is a rounded end or a spherical cap. [0094] In some embodiments, there is a continuity of curvature on transitioning from the neck portion to the head portion or on transitioning from the head portion to the neck portion.

[0095] In some embodiments, the head portion and the neck portion have different curvatures.

[0096] To form a matched pair of counterpart connection members, a counterpart connection member would have features which are opposite and complementary to that of the connection member of the first type and in matching correspondence in feature sizes, shapes and dimensions.

[0097] The protrusion member may have a circular symmetry or is circularly symmetrical about a center axis to facilitate coupling in different angular orientations about the center axis.

[0098] In embodiments where the protrusion member or a portion of the protrusion member is in the shape of a spherical segment or a spherical cap, the center axis of the protrusion member is coaxial with the center axis of the spherical segment or the spherical cap.

[0099] In embodiments where the protrusion member has a convexly curved peripheral profile which extends across and about the maximum transversal span, the protrusion member has a bulging profile about the maximum transversal span. [0100] In some embodiments, the protrusion member flares away from the base surface and extends along a linear path to form a frusto-conical neck portion or extends along a convex path to form a neck portion in the shape of a spherical segment.

[0101 ] In some embodiments, the protrusion member flares to reach a maximum transversal span, and the maximum transversal span is defined by a circular plane defining a sphere of the spherical segment and then tapers to reduce its cross-sectional area as it extends axially away from a height of the maximum cross-sectional area.

[0102] In some embodiments, the protrusion member flares to reach a maximum cross-sectional area and then tapers to reduce its cross-sectional area as it extends axially away from a height of the maximum cross-sectional area. [0103] In some embodiments, the connection members are adapted for interference-fit engagement or interference-fit in short, wherein a connection member of the first type is a male- type interference connector, a connection member of the second type is a female-type interference connector, and a pair of interference connectors comprising a male-type interference connector and a correspondingly shaped and sized matched female connector are in interference- fit engagement (or "coupled engagement") when the counterpart male and female connectors are interference-fitted together.

[0104] In example embodiments where the connection member of the first type is a male-type interference connector, the protrusion member comprises a substantially cylindrical or prismatic body, or a frusto-conical body which tapers monotonously to narrow as it extends away from the base surface.

[0105] In some embodiments, including the example of Figures 1 A and 1 E, the connection members are adapted for both interference-fit and snap-fit engagement, so that a connection member of the first type is a male-type snap connector, a connection member of the second type is a female-type snap connector, and a pair of snap connectors comprising a male-type snap connector and a correspondingly shaped and sized matched female connector are in snap-fit engagement (or "coupled engagement") when the counterpart male and female connectors are snap-fitted together.

Connection member of the second type

[0106] A connection member of the second type 142 has female type mating features and properties and is also referred to herein as a "female type connector", a female type connector member or a female connector in short where the context requires or is appropriate.

[0107] An example connection member of the second type comprises a coupling receptacle 146. The coupling receptacle 146, also referred to herein as a connector receptacle, comprises a receptacle body which defines a receptacle compartment. The receptacle compartment is for receiving an engagement portion of a matched counterpart connector of the opposite type, that is, a matched counterpart connection member of the second type. The receptacle body comprises an internal peripheral wall which extends between a first axial level and a second axial level to respectively define a first axial end and a second axial end of the receptacle compartment or the connector receptacle. The axial levels are at different levels along the axial direction and the axial direction is parallel to the centerline B-B' of the connection member and is orthogonal to the base surface. The first axial end of the receptacle compartment is proximal to the base surface and is defined by the first axial end of the internal peripheral wall of the receptacle body. The first axial end of the internal peripheral wall extends in a transversal circuit about a centerline of the coupling receptacle 146 to define an initial transversal clearance. The first axial end or the transversal circuit of the internal peripheral wall at the first axial end defines an entry aperture to the receptacle compartment and has a transversal span which defines an initial transversal clearance of the receptacle body at an entry end. The second axial end of the receptacle compartment is distal to an entry end where the entry aperture is defined. The transversal circuit of the internal peripheral wall at an axial level away from the base surface defines a transversal span at that axial level.

[0108] Referring to Figures 1 A to 1 D and 1 F, the second connection member 142 is a female- type snap connector, and the first axial end of the connector receptacle is at or is flush with the outward or downward facing surface 1401 of the second surface defining member 140.

[0109] The internal peripheral wall of the coupling receptacle comprises a first peripheral wall portion which is proximal to a downward facing surface 1401 of the surface bearing member 140 and a second peripheral wall portion which is distal to the base surface. The first peripheral wall portion extends in a transversal direction as a transversal circuit. The transversal direction is orthogonal to the axial direction and the axial direction is parallel to the centre line B-B' of the coupling receptacle. The first peripheral wall portion is a up standing wall which projects from a base. The base is joined to the surface bearing member by a bridging portion, with a peripheral groove formed between the first peripheral wall portion and the surface bearing member. [01 10] The internal peripheral wall of the coupling receptacle comprises a second peripheral wall portion which defines a receptacle base member. The receptacle base member projects in an axial direction away from the inward facing surface 1402.

[01 1 1 ] Each of the coupling receptacle, the receptacle body and the receptacle compartment is circularly symmetrical about the centreline to permit relative rotation between the coupling receptacle and a counterpart protrusion member in mated engagement connection therewith, and/or to permit the receiving coupling receptacle to enter into mated engagement connection with a counterpart protrusion member at different relative angular orientations about the centreline. The coupling receptacle has opposite and complementary mating features and properties to a counterpart protrusion member to facilitate mated engagement connection with a counterpart protrusion member.

[01 12] The first and second axial ends of the coupling receptacle are on the centreline of the coupling receptacle. The centreline of the coupling receptacle is also the centreline of the receptacle body and the centreline of the receptacle compartment.

[01 13] The receptacle body projects away from the base surface and extends along a second axial direction, the second axial direction being parallel to centreline. [01 14] The receptacle internal peripheral wall of the receptacle body is shaped and dimensioned to correspond to the shape and dimensions of a counterpart protrusion member of a counterpart connection member. For example, the receptacle internal peripheral wall may be shaped to define a receptacle compartment for receiving a connector head having a rounded free end, such as a rounded free end having the shape of a spherical cap, having a bulb shape or having the shape of a boss. In some embodiments, the receptacle internal peripheral wall is shaped to receive a protrusion member having spherical frustum body, or a cylindrical body having a narrowed base portion defined by a periphery extending groove or channel.

[01 15] In some embodiments, the coupling receptacle compartment comprising the collar compartment and the receptacle base compartment defines a continuous compartment for snap- fitted reception of an engaging portion having the shape of a spherical segment.

[01 16] The internal peripheral wall at the first axial end which defines an entry aperture to the receptacle compartment has a transversal span which defines an initial transversal clearance of the receptacle body at an entry end. The transversal circuit of the internal peripheral wall at an axial level away from the base surface defines a transversal span at that axial level.

[01 17] The internal peripheral wall (or the receptacle internal wall) flares to expand to increase its transversal span to reach a maximum transversal span as it extends away from the base surface in the axial direction (first axial end) and then tapers to converge to decrease its transversal span as it extends away from the maximum transversal span and towards its second axial end. [01 18] In some embodiments, the internal peripheral wall flares or diverges with a constant gradient or along a linear path as it extends away from the base surface to form a frusto-conical engaging portion.

[01 19] In some embodiments, the internal peripheral wall tapers or converges to narrow with a constant gradient or along a linear path as it extends away from the maximum transversal span and progress towards the second axial end to form a frusto-conical compartment.

[0120] The second axial end of the receptacle body is a rounded end having an axis of symmetry which is coaxial with the center axis of the receptacle body. The rounded second axial end defines a receptacle compartment having a dome-shaped or hemispherical distal end.

[0121 ] The internal peripheral wall flares or expand with an increasing gradient and defines a concave profile as it extends away from the base surface. The radial end of the internal peripheral wall forms a wedging end for engaging with a retention device on a counterpart connection member.

[0122] The internal peripheral wall tapers to narrow with an increasing gradient and defines a concave profile as it extends away from the maximum transversal span to form a rounded axial free end.

[0123] The internal peripheral wall has a concave profile which extends across the maximum transversal span as the internal peripheral wall progresses in the axial direction, the concave profiles on two axial sides of the maximum transversal span cooperate to form a bulging retention compartment which is part of the receptacle compartment. [0124] The portion of the internal peripheral wall between the base and the maximum transversal span is in the form of a spherical segment and/or has an outer peripheral surface which follows the shape and curvature of the curved surface of a spherical segment.

[0125] The internal peripheral wall has a concavely curved portion which is proximal to the base surface, the convexly curved portion form a peripherally extending wedging portion. [0126] In embodiments where the coupling receptacle is formed as a depression on a surface defining body, the internal peripheral wall cooperates with the base surface to form a peripherally extending wedging portion. The peripherally extending wedging portion is a wedging portion which progressively narrows, converges or tapers to narrow on extending radial inwards towards an axially extending centerline of the protrusion member. [0127] In embodiments where the internal peripheral wall tapers to narrow as it extends towards the base surface or flares to expand as it extends away from the base surface, the tapered or flaring end of the protrusion member makes an acute angle with the base surface. The acute angle is typically between 20 degrees to 85 degrees, for example, the acute angle may be 20 degrees or more, 25 degrees or more or less, 30 degrees or more or less, 35 degrees or more or less, 40 degrees or more or less, 45 degrees or more or less, 50 degrees or more or less, 55 degrees or more or less, 60 degrees or more or less, 65 degrees or more or less, 70 degrees or more or less, 75 degrees or more or less, 80 degrees or more or less, or 85 degrees or less, or a range defined by a combination of any of the aforesaid values and/or ranges. An example preferred range is 30 to 60 degrees. The joining angle is between 5 degrees to 70 degrees to the centerline, and the aforesaid angular values are each to be minus by 90 degrees if the joining angle is with reference to the centerline B-B' or axial line. [0128] In some embodiments, the internal peripheral wall flares from an initial transversal clearance at the first axial end to reach a maximum transversal span at an axial level of the maximum transversal clearance in an axial direction along the axis of circular symmetry. The axial height d2 between the first axial end and the axial level of the maximum transversal clearance is a fraction of W, where W is the transversal width at the maximum transversal clearance. The axial height d2 is in the region of 0%-100% of W, for example, 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% and/or any range or ranges selected from the aforesaid values.

[0129] In some embodiments, the internal peripheral wall tapers or converges to narrow from a maximum transversal clearance to reach a second axial end in an axial direction along the axis of circular symmetry, the axial height d1 between the axial level of the maximum transversal clearance and the second axial end of the receptacle body or receptacle compartment is in the region of 0%-100% of W, for example, 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% and/or any range or ranges selected from the aforesaid values.

[0130] In some embodiments, the maximum transversal clearance W equals the diameter of a sphere defining the coupling compartment and the maximum transversal clearance is defined by a circular plane encircled by the internal peripheral wall.

[0131 ] The axial height of the internal peripheral wall between the first axial end and the maximum transversal clearance may be determined with reference to the strength, rigidity and resilience of the materials of the protrusion member and/or the counterpart engagement member to be coupled with the protrusion member without loss of generality.

[0132] In embodiments where the portion of the internal peripheral wall between the first axial end and the maximum transversal clearance is a concavely curved portion having the shape of a lower spherical segment or bowl shape, the initial transversal clearance w at the first axial end has a transversal width which is a fraction of W, where W is the transversal width at the maximum transversal span. The initial transversal clearance w is between 55% to 95% of W, including 55% or more, 60% or more or less, 65% or more or less, 70% or more or less, 75% or more or less, 80% or more or less, 85% or more or less, 90% or more or less, 95% or less, or any range or ranges defined by any combination of the aforesaid values, range or ranges. A lower spherical segment herein is one where the maximum transversal clearance is a transversal span defined by a diameter of the sphere and is parallel to and spaced apart from the base surface. [0133] The internal peripheral wall may have a circular symmetry about a center axis to facilitate coupling in different angular orientations about the center axis.

[0134] Where the internal peripheral wall or a portion of the internal peripheral wall is in the shape of a spherical segment or a spherical cap, the center axis of the internal peripheral wall is coaxial with the center axis of the spherical segment or the spherical cap.

[0135] In embodiments where the internal peripheral wall has a concavely curved peripheral profile which extends across and about the maximum transversal span, the internal peripheral wall has a bulging profile about the maximum transversal span to define a middle bulging receptacle compartment. [0136] In some embodiments, the receptacle body defines a ball-joint socket or a bulb-shaped receptacle compartment or a dome-shaped receptacle compartment for snap-fit reception of a ball-shaped coupling head of a counterpart connection member. The internal peripheral wall may follow the curved surface of a spherical segment in order to form snap-fit coupling engagement with an engagement portion of a counterpart connection member having a spherical segment shape. For example, the maximum internal transversal span of the internal peripheral wall which defines the maximum transversal clearance of the collar portion that may equal to the maximum transversal span of a sphere defining the spherical segment. In other words, the maximum transversal clearance is defined by a circular periphery having a radius SR, where SR is the radius of the sphere defining the spherical segment. The axial span or thickness of the collar member may equal to t% of the radius SR of the sphere, where t% may be larger than 15% or 20%, for example, 15% or more, 20% or more or less, 25% or more or less, 30% or more or less, 35% or more or less, 40% or more or less, 45% or more or less, 50% or more or less, 55% or more or less, 60% or more or less, 65% or more or less, 70% or more or less, 75% or more or less, 80% or less, or any range or ranges formed by a combination of any of the aforesaid values and/or ranges.

[0137] In some embodiments, the receptacle body comprises a collar portion which extends around an internal boundary of the base surface to define an entry aperture to the receptacle compartment.

[0138] In some embodiments, the coupling receptacle includes an axial free end, the axial free end defining the entry aperture and being flush with the base surface of the surface defining member. [0139] The first axial end of the second connection member 142 is configured as a collar member 144. The collar member is an up-standing member which projects away from the second axial end in the axial direction and extends along a transverse circuit to surrounds the entry aperture to the receptacle compartment. A peripheral groove or channel is formed on the surface defining member 140 to surround the collar member. The peripheral groove or channel is an open channel with the channel bottom surface facing away from the second axial end. The peripheral groove or channel is formed as a depression on the second surface defining member 140, and the depth of the channel groove or channel defines or is equal to the axial height of the collar member 144. The collar member is a part or an extension of the hollow shell member and thickness of the collar member 144 is smaller than the thickness of the other shell parts of the hollow shell member. The peripheral groove provides a buffer space for lateral deflection of the collar member 144 so that when the internal peripheral surface of the collar member 144 is subject to an outward deflection surface, for example, when the internal peripheral surface of the collar member 144 encounters a slightly oversized engaging head of a protrusion member, the collar member 144 will deflect radially outwards into the peripheral groove.

[0140] The collar member defines a radial entry clearance or a transversal entry clearance which is smaller than the maximum transversal span of the head portion or the engaging head of a counterpart protrusion member so that the collar member 144 has to deform resiliently and to expand radially outwards to enlarge the inner boundary defined by its internal peripheral wall. When the engaging head moves in the axial direction and towards the second axial end in order to enter the receptacle compartment, the transversal clearance defined by the internal peripheral wall will be increased when the engaging head encounters the internal peripheral wall of the collar member. The peripheral groove 148 defines a clearance which is sufficiently large to permit a necessary and sufficient amount of radial outward deflection to permit through-passage of the engaging head on progressing into the receptacle compartment. In general, the width of the peripheral groove 148 at the downward facing surface 1401 of the surface defining member is comparable to, including equal to, or slightly larger than, the difference between the maximum transversal span and the radial entry clearance or a transversal entry clearance. Adjacent connection members or peripheral grooves 148 of adjacent connection members are connected by a web-like bridging portion which is a transversely extending portion of the sheet-like or platelike surface defining member 140.

[0141 ] In some embodiments, including the example of Figure 1 A, the inner periphery of the collar member is concavely curved as it extends between the first and second axial ends to define a concavely curved bulging receptacle compartment. The bulging receptacle compartment bulges in a transversal direction as it extends in the axial direction which is orthogonal to the transversal direction. The concavely curved bulging receptacle compartment is fit for reception of an engaging head of a counterpart connection member having a correspondingly matched convexly curved bulging head portion, for example, in the shape of a spherical segment shape, so that a snap-fit joint or a snap-fit coupling engaging with the engagement portion of the counterpart connection device. For example, the collar member 144 can function as a ball socket to receive a ball-shaped engagement portion of the counterpart connection member 122. The collar member inner periphery follows the curved surface of a spherical segment in order to form snap-fit coupling engagement with an engagement portion of a counterpart connection device having a spherical segment shape. For example, the maximum internal transversal span of the collar member inner periphery which defines the maximum transversal clearance of the collar member is equal to the maximum transversal span of a sphere defining the spherical segment. In other words, the maximum transversal clearance is defined by a circular periphery having a radius R, where R is the radius of the sphere defining the spherical segment. The axial span or thickness of the collar member may equal to h% of the diameter D of the sphere, where h may be larger than 1 5% or 20%, for example, 15% or more or less, 20% or more or less, 25% or more or less, 30% or more or less, 35% or more or less, 40% or more or less, 45% or more or less, 55% or more or less, 60% or more or less, 65% or more or less, 75% or more or less, 80% or more or less, 85% or more or less, 90% or less, or any ranges formed by a combination of any of the aforesaid values and/or ranges.

[0142] In general, the collar member inner periphery is to define a receptacle compartment having an initially flaring, diverging or widening compartment portion and a subsequently tapering, converging, or narrowing compartment portion for snap-fit retention of an engagement portion of a counterpart connection device

[0143] In some embodiments, the collar member inner periphery may be simply concavely curved without following the curvature of a sphere to define a generally concavely curved bulging receptacle compartment.

[0144] In some embodiments, the collar member inner periphery may follow the outer curved surface of a truncated cone or a frusto-cone to define the initially flaring, diverging or widening compartment portion and/or subsequently tapering, converging, or narrowing compartment portion. [0145] In some embodiments, the collar member inner periphery may have a combination of a frusto-conical portion and a spherical segment portion.

[0146] In some embodiments, the height or axial extend of the up standing portion of the collar member is less than the height or axial extent of the collar member. The height of the up standing portion of the collar member is about c% of the height or axial extend of the collar member, where c is typically in the region of 35% to 65%, for example, for example, 35% or more or less, 40% or more or less, 45% or more or less, 50% or more or less, 55% or more or less, 60% or more or less, 65% or less, or any ranges formed by a combination of any of the aforesaid values and/or ranges. [0147] The coupling receptacle 146 extends beyond the collar member to form a receptacle base member. The receptacle base member extends axially away from an axial end of the collar member which is distal to the entry aperture and projecting in the axial direction away from the collar member and comprises a free axial end which is distal to the collar member. The receptacle base member defines a receptacle base compartment which is for receiving a portion of engaging portion of a counterpart connection device which projects beyond the collar portion. The receptacle base member may define a receptacle base for receiving a spherical segment portion or of other shapes complementary to the shape of the portion of the engaging portion of a counterpart connection device which projects beyond the collar portion without loss of generality.

[0148] In some embodiments, the coupling receptacle comprising the collar compartment and the receptacle base compartment defines a continuous compartment for snap-fitted reception of an engaging portion having the shape of a spherical segment.

[0149] An example building block 100' comprises a first panel member 120' as an example of a first surface defining member on which a plurality or connection members 122' of the first type is formed, a second panel member 140' as an example of a second surface defining member on which a plurality or connection members 142' of the second type is formed and a peripheral panel member extending around a lateral periphery of the panel members 120', 140', as depicted in Figures 2A to 2F, 2A1 and 2A2.

[0150] In this example, the connection members are arranged in a two-row by two-column rectangular matrix and the panel members are rectangular. Otherwise, the building block, the connection members and other components have same, similar or equivalent features as those described herein and the relevant descriptions on connection members are incorporated herein by reference mutatis mutandis for the benefit of succinctness where appropriate and/or where the context allows, with reference numerals marked by an apostrophe (') where appropriate.

[0151 ] An example building block 400 comprises a first panel member 420 as an example of a first surface defining member on which a plurality or connection members of the first type 422 is formed, a second panel member 440 as an example of a second surface defining member on which a plurality or connection members of the second type 442 is formed and a peripheral panel member extending around a lateral periphery of the panel members 420, 440, as depicted in Figures 4A, 4B, and 4C.

[0152] In this example, radial grooves or channels are formed on the end cap portion of the protrusion members 422. Otherwise, the building block, the connection members and other components have same, similar or equivalent features as those described herein and the relevant descriptions on connection members are incorporated herein by reference mutatis mutandis for the benefit of succinctness where appropriate and/or where the context allows, with reference numerals increased by 300 where appropriate. [0153] An example building block 500 comprises a first panel member 520 as an example of a first surface defining member on which a plurality or connection members is formed, a second panel member 540 as an example of a second surface defining member on which a plurality or connection members is formed and a peripheral panel member extending around a lateral periphery of the panel members 520, 540, as depicted in Figures 5A and 5B. [0154] In this example, both connection members of the first type and connection members of the second type 522, 542, that is connection members of opposite mating features, are some on the same panel member. In addition, a through aperture is formed on the top of the end cap portion. Otherwise, the building block, the connection members and other components have same, similar or equivalent features as those described herein and the relevant descriptions on connection members are incorporated herein by reference mutatis mutandis for the benefit of succinctness where appropriate and/or where the context allows, with reference numerals increased by 400 where appropriate.

[0155] An example building block 300 comprises a panel member 320 as an example of a surface defining member, a plurality of connection members of the first type 322, a plurality of connection members of the second type 342, and a peripheral panel member extending around a lateral periphery of the panel member 320, as depicted in Figure 3A, 3B, 3C and 3D. The connection members of the first type 322 are formed and distributed on a first base surface of the panel member. The connection members of the second type 322 are formed and distributed on a second base surface of the panel member. The first base surface is on a first side of the panel member and the second base surface is on a second side of the panel member. The first base surface 3201 and the second base surface 3202 are parallel and oppositely facing surfaces of the panel member 320.

[0156] Connection members on the first base surface collectively define a first coupling portion which is configured for entering into mated mechanical coupled engagement with counterpart connection members of another building block along a first coupling direction.

[0157] Connection members on the second base surface collectively define a second coupling portion which is configured for entering into mated mechanical coupled engagement with counterpart connection members of another building block along a second coupling direction which is parallel to but opposite to the first coupling direction. The coupling direction is a direction orthogonal to the base surface and is a direction which is parallel to the axis of circular symmetry of a connector member forming a coupling portion. The axis of circular symmetry of the connector member defines an axial direction in relation to the connector member.

[0158] Referring to Figures 3A and 3B, the connection members are arranged into connector pairs, and the connection pairs are arranged in a matrix. Each connector pair comprises a connection member of a first type on one side of the panel member and a connection member of a second type on another opposite side of the panel member, and corresponding connection members of the first type and the second type forming a connector pair are axially aligned.

[0159] The connection member of the first type 322 is a male type connector comprising a protrusion member which projects from a first base surface 3201 of the panel member and extends in the axial direction 320. The protrusion member is defined by a hollow shell member having an internal cavity which is aligned with an intermediate aperture defined on the panel member. The connection member of the second type 342 is a female type connector comprising a connector receptacle which projects from a second base surface of the panel member and extends in an opposite axial direction. The connector receptacle has a receptacle body defining a receptacle compartment. The receptacle body comprises a receptacle peripheral member having an internal peripheral wall defining the receptacle compartment and an external peripheral wall surrounding the internal peripheral wall. The receptacle body is a hollow shell member defined by a shell-like receptacle peripheral member. Thickness of the receptacle peripheral member is comparable to or smaller than the thickness of the panel member generally. As the receptacle peripheral member is also joined to the panel member, the building block has connection members of opposite mating types on opposite sides of and sharing the same panel member.

[0160] The internal peripheral wall of the receptacle body is shaped to receive a bulging engagement portion of a protrusion member and resembles a ball-joint socket. In some embodiments, the internal peripheral wall of the receptacle body is shaped to receive a cylindrical or a non-bulging engagement portion of a protrusion member. The external peripheral wall of the receptacle body extends along a circular path in a transverse direction to define a substantially cylindrical receptacle body having its cylindrical axis aligned or coaxial with the connector member axes. The receptacle peripheral member projects away from the panel member like a funnel, as shown in Figure 3B, and the space in the vicinity of the receptacle peripheral member is cleared to permit radial outward deflection when encountering a bulging engagement portion of a counterpart protrusion member. The volume defined by the panel member in cooperation with the peripheral panel member is empty or hollow except at locations where the receptacle bodies are present.

[0161 ] Adjacent connection pairs are connected by transverse portion of the panel member as a transverse bridging portion or an interconnection portion. The hollow shell member of the protrusion member comprises an end cap portion at its top end and a peripheral portion interconnecting the panel member and the end cap portion. The hollow shell member connects adjacent bridging portions of the panel member and provides supplemental structural strength. The end cap portion is arcuate and extends radially or transversely across the intermediate aperture. A through passageway is formed between the protrusion member and the receptacle body, and the through passageway is formed by the portion of the panel member defining the intermediate aperture. [0162] The connection members and other components have same, similar or equivalent features as those described herein and the relevant descriptions on connection members are incorporated herein by reference mutatis mutandis for the benefit of succinctness where appropriate and/or where the context allows, with reference numerals increase by 200 where appropriate.

[0163] The height of the receptacle body or the receptacle compartment defined by the receptacle body in this example is less than the radius of a defining sphere, which defines the spherical surface curvature of a bulging engagement portion of a protrusion member. Where the bulging engagement portion of a counterpart protrusion member has a height larger than the height of the receptacle compartment, the excessive height will project into the intermediate aperture so that the intermediate aperture forms a supplemental or secondary receptacle compartment.

[0164] The formation of connection members having opposite mating properties on the same panel member as herein described facilitates compart and lightweight construction with enhanced structural strength.

[0165] In some embodiments, the connector pairs are arranged such that connection members of the same mating properties are formed on both sides of the panel member and/or connection members of the opposite mating properties are accessible from one side or both sides of the panel member. [0166] While various examples have been shown and described herein, it should be appreciated that the examples are non-limiting examples only. For example, while the example connection members on a building block are matched counterpart connection members, the connection members on a same building block can contain both matched and unmatched connection members without loss of generality. [0167] In some embodiments, the hollow shell member of the connection member joins the surface defining member at right angle (that is, at 90 degrees) or at an obtuse angle (that is, 90 degrees or more) to the surface defining member. A connection member of the first type having such a hollow shell member may have a peripheral groove or channel, or a circumferential groove or channel extending around the neck portion to facilitate snap-fit and/or interference-fit engagement. The groove or channel may be continuous or non-continuous, for example comprising a plurality of discrete, discontinuous, broken or intermittent portions without loss of generality.