TECHNICAL FIELD AND BACKGROUND ART This invention relates to puzzles of the kind solved by moving a series of elements into particular positions relative to one another. Such puzzles may be generally two dimensional, for example jigsaw puzzles, or three dimensional, for example the very popular "magic cube" puzzles. Most puzzles of this general kind involve the building of a surface pattern, for example to produce a picture or to match coloured panels or faces. The present invention provides a puzzle the solution of which presents more of a spatial problem involving the

σonstruction of a shape which is of particular interest since it occurs frequently in nature, namely a continuous spiral.

DISCLOSURE OF INVENTION According to the invention there is provided a puzzle comprising a series of relatively movable elements positionable relative to one another so as together to form a continuously spiraled figure.

Preferably the spiraled figure is shaped to a logarithmic spiral. It may be essentially a two dimensional figure into which case said elements may be generally planar or it may be a three dimensional figure, particularly a nautiloid figure i.e. a figure based on the shape of the nautilus shell. The movable elements may be entirely separable from one another and capable of being moved independently into the positions in which they form said figure. Alternatively they may be held together by inter¬ connecting means permitting limited degrees of relative movement between them.

In one particular kind of puzzle constructed in accordance with the.invention, the spiraled figure is a nautiloid figure, the relatively movable elements form sectors of the nautiloid figure between radial planes radiating at equal angular intervals from the polar axis of the spiral, and the elements are held by inter¬ connecting means which permit relative rotation between the sector elements to one side of any of the radial planes and the sector elements to the other side of that plane.

There may be eight elements defining sectors each having a sector angle of 45°. In this case any four sectors will be rotatable relative to the remaining four sectors.

Preferably the interconnecting means is substantially concealed by the movable elements.

The interconnecting means may, for example, be comprised of a central element on which the relatively movable elements are rotatably mounted. Such mounting may be achieved by magnetic attraction. More particularly the central element may be a ball of magnetic material and the elements may be fitted with magnets which hold them to the ball but permit rotation thereon.

BRIEF DESCRIPTION OF DRAWINGS In order that the invention may be more fully explained one particular embodiment will be described in some detail with reference to the accompanying drawings in which:-

Figure 1 is a perspective view of a puzzle having movable elements defining sectors of a nautiloid figure;

Figure 2 is a cross-section through the nautiloid figure;

Figure 3 is a composite of three cross-sections on the lines A-A, B-B and C-C in Figure 2;

Figure 4 is an exploded perspective view of a typical sector of the nautiloid figure; Figure 5 is a perspective view of the typical sector when assembled; and

Figures 6(a) to 6(e) illustrate diagrammatically the manner in which the various sectors can be moved relative to one another.

BEST MODE OF CARRYING OUT INVENTION

The illustrated puzzle comprises eight relatively movable elements defining sectors 1 to 8 of a nautiloid. The eight sectors have equal sector angles of

OMPI WIPO

45° each and when correctly positioned relative to one another form a complete nautiloid figure having a smoothly continuous surface formed of a logarithm spiral. The eight elements defining the sectors 1 to 8 are of similar shape and proportion but increase progressively in size. They are arranged around a central steel ball 12 and they are fitted at their inner ends with magnets 13. They are thus held to each other and to the central ball by magnetic flux in such a manner that they can be rotated about the ball.

Figures 4 and 5 illustrate the construction of a typical sector of the puzzle comprising two matching pieces 14, 15 which may be injected moulded plastic and which can be snap fitted together to form a hollow casing or shell of the sector. Pieces 14, 15 have inwardly projecting bosses 16, 17 which are notched so as to provide edge supports for the respective magnet 13 and a pair of mild steel magnet pole plates 18. The magnet and the pole plates are thus held sandwiched together on assembly of the sector element. This sandwich arrangement maximises the magnetic flux.

Detents are provided at the sector interfaces to inhibit undesired inter-sector movement. These detents comprise detent balls 19 loaded by springs 20 within detent housings moulded into the sector pieces 14, 15 and matching detent cavities 21 formed in the external faces of pieces 14, 15.

Sectors 1 to 7 may be of identical construction except for size but sector 8 is modified slightly to form an exterior cavity 22 providing an open mouth for the nautiloid figure. The modification merely requires the moulding of the cavity 22 in the outer part of one of the respective shell pieces and a corresponding reduction in the size of the matching piece.

The magnets 13 are disposed radially in the- equatorial plane, with their poles opposed (N to S) in adjacent sectors when the puzzle is in its ordered or resolved state thereby producing a closed annular magnetic circuit. Consequently, when the puzzle is in its ordered condition, the sectors are strongly held together by the magnets without the need for the central steel ball. When the puzzle is scrambled, the magnets of some adjacent sectors may repel each other but the puzzle will still be held together by their attraction to the steel ball.

The sectors 1 to 8 are held together by magneti'c forces but can be freely rotated in any of the radial planes defined between the sectors. More particularly any four sectors together may be rotated 180° relative to the remaining four sectors. This rotation inverts and transposes sectors to opposite sides about the rotational axis in the equatorial plane.

Performing a few random rotations of puzzle "halves" (various sets of four sectors) very quickly produces a scrambled state, with the sectors disordered and disoriented. The object then is to return the puzzle to its original state. This is surprisingly difficult and generally the solution can not be achieved by simple trial and error. A systematic approach or algorithm is required and, significantly, routes to resolution of the puzzle call for a partial or temporary destruction of the order already achieved.

The manner of movement of the various sectors of the puzzle and sequential moves toward resolution are illustrated diagrammatically in Figures 6(a) to 6(e), which show five successive states of the puzzle moving from a disordered state to the desired ordered state in which the sectors are correctly arranged in a counter- clockwise sequence.

If the puzzle is inverted as a whole at any stage the puzzle spiral direction is reversed as the sectors reverse direction on rotation.

The detent balls 19 and cavities 21 provide a positive registration between the sectors at the specific orientations between rotational movements. The spring- loaded balls are able to ride over the adjacent detent balls encountered during each rotation, thus ensuring continuous contact between the magnets 13 and the central steel ball ^" 12.

As an aid to younger children temporary numbered labels may be attached to the sectors, for example numerals 1 to 8 in red on one side and 1 to 8 in green on the other side. This simplifies resolution and builds number sense but at the expense of spatial learning. A great deal of the puzzle's difficulty and challenge lies in predicting sequential orientations of the sectors.

The illustrated puzzle has been advanced by way of example only and it could be modified considerably. For example the number of sectors could be increased or reduced. The mode of construction of the sectors and the interconnecting means holding them together could also be changed. In a simple form of the puzzle the elements could be completely separable from one another and the ^! puzzle solved by interfitting the individual pieces together. Other spiral figures could be adopted.