SUMMARY OF INVENTION It is an object of the invention to provide an improved or at least alternative form of product to assist learning or for entertainment or recreation.

In broad terms the invention comprises a learning or games product such as a book, board or card, calendar or the like, having a question section comprising at least one printed question or problem, statement or image, and at least one second section comprising a re-writable panel where an answer or solution to the question or problem, statement or image, can be written and subsequently erased for reuse of the panel.

Preferably the product also comprises at least one third section forming a correct answer panel where the correct answer or solution to the question or problem, statement or image of the first section or can be caused to be displayed.

In the product of the invention a learning or games question or problem is presented in the question panel and the users answer is written in the answer panel. The written answer

can later be erased from the "answer panel", in a preferred form of the invention by wiping a users finger across the answer panel as will be described. Similarly in preferred forms of the invention which also comprise a correct answer panel, the correct answer can be displayed or then caused to disappear from the correct answer panel, in a preferred form of the invention also by wiping a users finger across the panel.

The invention is intended for, but not limited to, educational and entertainment or recreational purposes. In education many books are used for teaching children cursive skills and other similar repetitive writing drills such as time telling and mathematics etc and the invention can be used to assist such learning. For example, pages of a book or one or more learning boards or slates of the invention may each comprise a question section comprising one or more questions relating to multiplication tables e.g. 1 x 7, 2 x 7, 3 x 7 ... 11 x 7, 12 x 7. Many types of questions can be asked and specific skills taught using a book or similar of the invention. An answer can be written in the rewritable answer panel by the student or user and then checked, and once the answers have been checked they can be erased so that the book or similar can be reused later. Similarly, spelling can be taught by providing images of common objects such as cat, dog, ball, house, sun, clouds etc in the question section.

In preferred forms of the book or similar which also include a correct answer panel an answer is written by the student or user in the re-writable answer panel while the correct answer is concealed, and the correct answer panel can then be rubbed down to make the concealed answer visible. Once the answers have been checked both the answer and correct answer panels can be erased for use later.

Time telling can also be taught effectively with the invention. A picture of a clock can form the question panel and the time can be written in the re-writable answer panel and checked then by the student such as a child against the correct answer panel. Books, boards, games, cards and similar of the invention have many applications.

The structure of the answer panel comprises a base layer of contrasting colour and an upper sheet extending over the base layer, which upper sheet and base layer are sufficiently releasably adhesive together under pressure applied to the product by a writing implement on the upper sheet to cause the upper sheet and the base layer to adhere in the localised region in contrast to the balance of the upper sheet, the upper sheet being subsequently releasable from the base layer to erase the answer.

Preferably the answer panel structure allows the upper sheet to be moved relative to the base layer to erase the answer

panel when a users finger or thumb is wiped across the top of the upper sheet.

In preferred forms the upper sheet of the answer panel also extends over a "wipe-start" region adjacent the base layer. In this wipe-start region the upper sheet and the base layer are not adhesive together. A users finger or thumb may begin the wiping movement to separate the upper sheet from the base layer to erase the answer panel from this wipe-start region.

In use an answer is written on the answer panel for example with a blunt instrument such as a blunt stylus, a pen or pencil (preferably the non-marking end) or similar. To subsequently erase the answer panel a user's finger is wiped under moderate pressure from the "wipe-start" region across the answer panel over the written answer, which is thereby erased. Other structures to release the upper sheet from the base layer may be used however. For example the upper sheet may be attached to the base sheet along one edge only, so that it can be peeled from the base layer to erase the label, or a slidable cursor between the upper sheet and base layer could be provided.

In one form the "correct answer" panel where provided may comprise a base layer comprising an answer in a suitable contrasting colour in or below the base layer, an upper sheet extending over the base layer, the upper sheet and base layer being releasably adhesive together under pressure applied on the

upper sheet for example with a blunt writing instrument to cause the upper sheet and the base layer to adhere so that the answer is visible through the upper sheet and the upper sheet being releasable from the base layer to subsequently remove or substantially remove the answer from display.

In this form of correct answer panel the answer is in or beneath the base layer. To cause the answer to "appear" the upper sheet is pressed against the base layer to adhere to the base layer. To release the upper sheet from the base layer to cause the answer to disappear or substantially disappear a users finger or thumb is wiped across the top surface of the upper sheet from one side to the other, to cause the upper sheet to move relative to and be separated from the base layer.

In another form the "correct answer" panel where provided may comprise a base layer, and an upper sheet extending over the base layer and having an answer printed in a suitable colour on the upper sheet, the upper sheet and base layer being releasably adhesive together under pressure applied on the upper sheet, whereby the answer on the upper sheet is visible only when the upper sheet is released from the base layer, and when pressure is applied to the upper sheet for example with a blunt writing instrument to cause it to adhere to the base layer the answer becomes not clearly visible. The answer may be printed on the underside or top of the upper sheet, as a positive or negative image.

In this above form of correct answer panel the answer is printed in a suitable colour on the upper sheet. When the upper sheet is pressed against to adhere to the base layer of the correct answer panel the answer "disappears" so that it is blocked out to be invisible, or at least not clearly visible. When the upper sheet is released from the base layer the printed answer on the upper sheet becomes visible or substantially visible again.

In both of the appearing and disappearing forms of correct answer panels described above, preferably the structure of the correct answer panel is such that to release the correct answer upper sheet a users finger or thumb may be wiped across the top surface of the upper sheet from one side to the other, to cause the upper sheet to move relative to the base layer, as described for the answer panel. Other structures to release the upper sheet from the base layer may be used however. For example the upper sheet may be attached to the base sheet along one edge only, so that it can be peeled from the base layer to erase the label, or a slidable cursor between the upper sheet and base layer could be provided. Alternatively again the correct answer panel could use heat sensitive inks i.e. the answer could be printed in the correct answer panel with one or more heat sensitive or thermochromic inks, so that when the user, such as a child, places his finger on the correct answer panel for a few seconds the correct answer will be displayed and will then disappear.

DESCRIPTION OF DRAWINGS Preferred forms of the invention will now be described by way of example and without intending to be limiting as to detail, with reference to the accompanying drawings, wherein:

Fig. 1 shows an area of a page of a book, a card or similar of one form of the invention comprising a question section and an answer panel.

Fig. 2 shows an area of a page of a book, a card or similar of another form of the invention comprising a question section, an answer panel, and a correct answer panel with questions displayed in a question section and with the answer and correct answer panels blank.

Fig. 3 shows the area of Fig. 2 with answers written into the answer panel.

Fig. 4 shows the area of Figs 2 and 3 with the correct answers also displayed in the correct answer panel.

Figs 5, 6 and 7 show areas of a page of a book, a card or similar of the invention similar to that of Figs 2 to 4;

Fig. 8 shows a preferred form answer panel blank;

Figs 9 and 10 show erasure of an answer from the preferred form answer panel of Fig. 8;

Fig. 11 shows the answer panel of Figs 8 to 10 in cross-section;

Fig. 12 shows one preferred form of correct answer panel with the correct answer "erased" i.e. not displayed;

Fig. 13 shows the correct answer panel of Fig. 11 with the upper sheet and base layer of this form of correct answer panel separated so that the correct answer which in the example shown in the drawings is the word CAT is clearly visible;

Fig. 14 shows the correct answer panel of Figs 12 and 13 in cross section;

Fig. 15 shows a second preferred form of correct answer panel with the correct answer "erased" i.e. the upper sheet released from the base layer so that the answer which in this case is the word DOG is not clearly visible;

Fig. 16 shows the correct answer panel of Fig. 15 with the upper sheet pressed against the base layer so that the answer is clearly displayed;

Fig. 17 shows the correct answer panel of Figs 14 and 15 in cross section;

Fig. 18 shows a third preferred form of correct answer panel in one state i.e. with the upper sheet released from the base layer so that an upper sheet icon (an apple shape in negative image) is visible and the answer of the base layer which in this case is the word "apple" is not clearly visible;

Fig. 19 shows the correct answer panel of Fig. 18 with the upper sheet adhered to the base layer so that the base layer answer (the word "apple") is visible within the negative image upper sheet icon;

Fig. 20 shows a correct answer panel similar to that of Figs 18 and 19 but slightly different, with the upper sheet pressed against the base layer so that the base layer answer is visible but (in this version) the upper sheet icon or indicia is less visible;

Fig. 21 is an exploded view of the correct answer panel of Figs 18 and 19;

Fig. 22 shows the correct answer panel of Figs 18 to 21 in cross-section;

Fig. 23 shows a form of correct answer panel incorporating a discontinuity in the wipe-start area to assist easy erasure;

Fig. 24 shows the correct answer panel of Fig. 23 showing erasure of the correct answer panel;

Fig. 25 shows the correct answer panel of Figs 23 and 24 in cross-section along line B-B of Fig. 24; and

Fig. 26 shows the correct answer panel of Figs 23 and 24 in cross-section along line C-C of Fig. 24.

DETAILED DESCRIPTION OF PREFERRED FORMS Referring to the drawings. Fig. 1 shows an area or surface which may be a page of a book or a part of a page of a book, a separate card from a pack of learning cards for example, or similar. In this example the objective is to teach the times tables. A question panel indicated at 1 comprises questions to be answered, such as times tables questions as shown, which may be permanently printed onto the book page, card etc. Times tables are shown only as an example and the printed questions could comprise any other educational or entertainment or recreational questions or problems such as pictures of words to be spelt, trivial pursuit type questions, abstract games problems, problems involving images of shapes, and so forth. An answer panel 2 is provided adjacent the question section 1 in

which a person writes their answers. The answers may be written in the answer panel with a blunt stylus, a fingernail or similar. The answers may then be checked, and then the answer panel 2 erased for reuse. The mechanical structure of the answer panel 2 which enables the answers to be written and subsequently erased, preferably with a finger wipe action from a wipe start region 4, which assists the finger wipe erasure action, will be described further. The wipe-start region 4 may be larger (or smaller) than the adjacent panel 2.

Fig. 2 shows an area which may again be a page of a book or a part of a page of a book, a separate card etc which is similar to that of Fig. 1 but also comprises a correct answer panel 3. The question section 1 and answer panel 2 are similar to those of Fig. 1. Fig. 2 shows both and answer panel 2 and the correct answer panel 3 blank. Fig. 3 shows answers written in the answer panel 2 to the questions shown in the question section 1. Once the answers have been written in the answer panel 2 by a child for example as shown in Fig. 3, then the correct answers may be caused to be displayed in the correct answer panel 3 as shown in Fig. 4. The child may then check his or her answers written in the answer panel 2 against the correct answers in the correct answer panel 3. After use, all of the answers in the answer panel 2 may be erased. Preferably a wipe-start area 4 is provided adjacent the answer panel 2. The correct answers are permanently marked but may be caused to be displayed for checking against the students answers written in the answer area 2, and

may also be caused to subsequently disappear or substantially disappear for re-use. The correct answers in the correct answer panel 3 may be caused to substantially disappear by similar finger wipe action. The product can then be re-used in exactly the same way as before by the same or a different person. The mechanical structure of the answer and correct answer panels will be described further.

Fig. 5 shows a variation of Figs 2 to 4 wherein instead of the answer panel 2 and correct answer panel 3 being provided as vertical panels adjacent a column of questions, small separate panels are provided for each adjacent each question as shown.

Fig. 6 shows a variation of Fig. 5 wherein instead of the answer panel and correct answer panels each having their own wipe-start region 4, a common (and larger) wipe-start area 4 is provided for the answer panel 2 and correct answer panel 3.

Fig. 7 shows a variation for teaching time. In this case the clock face 1 forms the question section and the objective is for a child to be assisted in learning to tell the time. The child writes the time that he or she believes the hands on the clock face to show in the adjacent answer panel 2. The correct answer may be caused to be displayed as shown in the correct answer panel 3. The answer panel 2 may be erased and the correct answer caused to disappear for re-use as before.

DETAILED DESCRIPTION OF PREFERRED FORM OF "ANSWER" PANEL CONSTRUCTION Referring to Figs 8 to 11, the preferred form "answer" panel comprises a base layer 5 and an upper sheet 6. The base layer 5 may be directly applied to the page of a book, the surface of a card or similar indicated at 7 in Fig. 11. The base layer 5 may be a wax or similar synthetic material coated onto the book page or similar and which will adhere suitably to the upper sheet 6. The base layer may be coloured for example dark blue, or alternatively any other desired colour or combination of colours in different regions.

Suitable materials for forming the base layer include waxes such as paraffin wax, blends of paraffin wax with other waxes, blends of other waxes, and other substances such as synthetic wax like substances having a waxy consistency, which can be applied as a thin layer and will adhere suitably with the upper sheet. Some base layers such as some synthetic wax-like base layers may be coloured by having a suitable dye or pigment added, or alternatively the base layer may be made to appear coloured by printing a colour on a substrate and then applying a clear or near clear wax or similar material over the coloured surface to form a coloured base layer.

The base layer may comprise any other suitable material than wax, which will adhere with the upper sheet 6 under localised manual pressure such as pressure of writing but which

also allows the base layer and top sheet to be subsequently separated to erase the answer panel. It is possible that the material of the book page, card surface or similar could form the base layer so that the base layer 5 and back page etc are one and the same.

The upper sheet 6 is preferably translucent and may comprise a translucent plastic film, tracing paper or the like. A clear plastic film may be given qualities of translucence by etching, texturing or calendaring the film and particularly the bottom surface of the film, for example. This may also assist the upper sheet to adhere with the base layer in use. A clear film may also be made translucent by printing the film with a translucent ink or a layer of a conventional opaque ink which is thin enough to make the film appear translucent. The upper sheet 6 may be printed to define a window in the upper sheet for example in which the answer is written. Most preferred for forming the upper sheet are polyester films or similar materials preferably having a glossy or substantially glossy surface. Preferably the upper sheet is up to 100 microns and most preferably in the range 35 to 65 microns in thicknesses.

A protective top sheet (not shown) may be provided over the upper sheet, comprising clear plastic film for example.

Adjacent the base layer 5 is optionally provided a wipe-start region 4. In Figs 8 to 10 this wipe-start region 4

is indicated by a broken outline. The wipe-start region may De formed as shown in Fig. 11 by applying no material of the base layer i.e. no waxy or similar material, to the surface beneath the upper sheet 6 in the wipe-start region 4. The region 4 may be the same width as the base layer 5 but could be of less or greater width, and is preferably at least one finger width wide in the direction of erasure along the length of the answer panel, but could be wider or longer.

The upper sheet 6 extends over both the base layer 5 and erase-start region 4 and is fixed to the surface 7 about all or most of the periphery of the upper sheet, that is along both sides and at either end of the upper sheet, by gluing, plastic welding or other suitable means during manufacture. Alternative to fixing the upper sheet about the entire periphery upper sheet, the upper sheet may be fixed along at least two opposite sides of the upper sheet or at least most of two opposite sides (in the case of a square or rectangular panel) but it is preferred to fix the upper sheet about most or all of the periphery of the upper sheet.

The upper sheet may additionally or alternatively be tinted with a different colour relative to the colour of the base layer, so that the answer panel normally appears to have the colour of the upper sheet and when written on the writing appears in the colour of the base layer, or in a colour resulting from the combination of the base layer and upper sheet colour. For

example, the base layer may be coloured blue and the upper sheet toned yellow; when pressed or adhered together under localised pressure of writing the writing will appear green in contrast to the balance of the yellow upper sheet. The colours could be luminescent or fluorescent. The upper sheet may also be made luminescent or fluorescent or may be lightly embossed with a pattern or logo for example which may be present as a hologram printed onto the upper sheet. The hologram may be provided in the upper sheet under a clear top laminated layer i.e. trap printed.

The arrangement is such that a blunt stylus, a pencil or pen (preferably the non-inking/marking end so as not to permanently mark the panel) or any suitable hard object may be used to write answers on the answer panel by pressing on the upper sheet 6 over the base layer 5. This will cause the upper sheet 6 to adhere to the base layer 5 where localised pressure from the writing implement is applied so that the colour of the base layer is then clearly visible through the translucent upper sheet 6. Fig. 8 shows the answer panel blank, after erasure, and Figs 9 and 10 show an answer written on the answer panel which is in this case the number 7.

To subsequently erase the answer from the answer panel a users finger or thumb is placed on the erase-start region 4 as shown in Fig. 9 and wiped across the top surface from the wipe-start region 5a as shown in Fig. 10. Even though the top

surface is substantially smooth, this will separate the upper sheet 6 from the base layer 5, erasing the written answer as the user's finger moves. The answer panel may then be rewritten on as before.

Where a wipe-start region 4 is provided, in an alternative arrangement the material of the base layer 5 may extend beneath the upper sheet 6 in the wipe-start region 4, and to make the upper sheet 6 and base layer 5 non-adhesive together in the wipe-start region, a release coating such as a silicon coating is applied to the under surface of the upper sheet 6 in the wipe-start region 4. Alternatively such a coating may be applied to the top surface of the base layer 5 in the wipe-start region 4.

The wipe-start region 4 does not need to be just adjacent one side of the answer panel but can surround the periphery of or be placed centrally within the answer panel, for example.

DETAILED DESCRIPTION OF DISAPPEARING FORM OF

"CORRECT ANSWER" PANEL Referring to Figs 12 to 14 one preferred form of "correct answer" panel comprises a base layer 5 similar to the base layer 5 of the answer panel, which is similarly carried by the page of a book 7, the surface of a card or similar (adjacent a related answer panel) . The base layer 5 is a wax or similar

synthetic material which will adhere with an upper sheet 6 similar to the answer panel of Figs 8 to 11. The upper sheet 6 also comprises a translucent film generally similar to the upper sheet 6 of the answer panel.

An answer is printed on the upper sheet 6 which answer in the drawings is the word CAT. The word CAT may be printed as a positive image in a colour similar to the colour of the base layer 5 as indicated at 6a on the underside of the upper sheet 6, or in a suitable colour on the top of the upper sheet 6. Alternatively the area around the word CAT may be printed so that the word CAT appears as a negative image i.e., the word itself remains as the translucent material with the word possibly being given a tint of for example yellow or orange by printing (without loss of the translucent quality) .

To cause the answer CAT to disappear or substantially disappear the upper sheet 6 is pressed against the base layer 5, for example by pressing and wiping a fingernail or suitable stylus over the upper sheet 6 to "block in" the required area. This will cause the upper sheet 6 to adhere to the base layer 5 and the word CAT will then merge into the colour of the base layer where the word has been printed as a positive image, or the colour of the base layer will become visible through the word CAT when printed as a negative (translucent) image so that the entire area will be blocked out, in a dark colour if the base layer is also a dark colour for example, as shown in Fig. 12.

To cause the correct answer CAT to appear, a users finger or thumb is wiped across the top surface of the correct answer panel in the same way as shown in Figs 9 and 10 for the answer panel. This will separate the upper sheet 6 and the base layer 5 as the user's finger moves, so that the answer CAT will become visible. The correct answer panel may be provided with an adjacent wipe-start area (not shown in Figs 12 to 14) to assist the finger wipe action, like the wipe-start area 4 of the answer panel of Figs 8 to 11.

To assist in making the correct answer less visible when the upper sheet 6 is adhered to the base layer 5 the top side (or under side) of the upper sheet 6 may have printed onto it a pattern of small opaque dots or wavy lines or similar which will further assist in tending to obscure the correct answer. Such a pattern of dots or wavy lines or similar should not be sufficiently dense or large to obscure the answer when the upper sheet is separated from the base layer 5 to make the answer visible.

The word CAT may be substituted by any other one or more words, numbers, pictures or other icons or indicia representing correct answers to questions of the question section.

DETAILED DESCRIPTION OF APPEARING FORM OF "CORRECT ANSWER" PANEL Referring to Figs 15 to 17 another form of "correct answer" panel comprises a similar base layer 5 carried by the page of a book 7, the surface of a card or similar, and an upper sheet 6. In this form of correct answer panel the base layer 5 is in the shape of the answer such as the shape of a number, letter, word, picture or similar and again is a wax or similar synthetic material which will adhere with the upper sheet 6 as indicated previously. The base layer 5 may be coated onto the page or card surface etc as a positive or negative image of the correct answer and may include a dye, so that the base layer is coloured for example dark blue, or alteratively any other desired colour or combination of colours in different regions and the upper sheet 6 is preferably translucent and may comprise a translucent plastic film, tracing paper or the like.

In use to cause the correct answer to be displayed the upper sheet 6 is pressed, for example by wiping a fingernail or suitable broad stylus over the upper sheet to block in the required area. This will cause the upper sheet 6 to adhere to the base layer 5 so that the answer is then clearly visible through the translucent upper sheet 6 as shown in Fig. 16. To "erase" the correct answer panel so that the correct answer is no longer visible or becomes at least substantially invisible, a users finger or thumb is wiped across the top surface as described previously for erasure of the answer panel of Figs 8

to 11. Even though the top surface of the label is substantially smooth, this will separate the upper sheet 6 and the base layer 5 as the user's finger moves. Again, an adjacent wipe-start region (not shown in Figs 15 to 17) may be provided to assist the finger wipe action, like the wipe-start region 4 of the preferred form answer panel of Figs 8 to 10.

In another form of this correct answer panel the answer may be ink printed in a suitable colour on the book page, card surface or similar and the base layer 5 may then comprise a coating of clear or near clear wax or similar over the whole of the book page or card surface which is applied after ink printing the answer. When the upper sheet is pressed against the base layer the upper sheet will adhere to the base layer and the ink printed answer behind the base layer will become substantially more visible through the upper sheet. The panel may be erased as before.

To assist in making the correct answer less visible when the upper sheet 6 is not adhered to the base layer 5, the colour of the correct answer base layer 5 may be made only medium contrast rather than high contrast, and also the top side or under side of the upper sheet 6 may have printed onto it a pattern of small dots or wavy lines or similar which will tend to hide any shadowy image of the correct answer that may still be visible through the upper sheet. Such a pattern of dots or wavy lines or similar should not be sufficiently dense or large

to obscure the answer when the upper sheet is pressed to adhere to the base layer 5 to make the answer visible. Such a pattern of dots or wavy lines or similar may be printed with a translucent ink, or even with an opaque ink where the pattern is not too dense.

In yet another form of appearing correct answer panel, similar to that of Figs 15 to 17, the coloured base layer 5 is continuous and a clear or substantially clear release or non¬ stick coating is applied over the top of the base layer 5 except in a region defining the shape of the answer i.e. the coating is applied as a negative image of the answer on top of the base layer 5 (but the coating could also be applied as a positive image). When the upper sheet 6 is pressed down by running an object over the upper sheet 6 the upper sheet 6 will adhere to the base layer where the coating is not applied but will not adhere to the coating so that the answer will be visible through the upper sheet. To erase the answer so that it is no longer clearly visible a user's finger or thumb is wiped across the top surface of the upper sheet 6 as before.

In another form of appearing correct answer panel of the invention the correct answer is printed as a preferably negative image (but could be positive) on the upper sheet preferably on the under side of the upper sheet. To cause the answer to appear, the upper sheet is pressed against the backing sheet, for example, by pressing and repeatedly running a

fingernail or suitable stylus over the upper sheet. This will cause the upper sheet to adhere to the base layer so that the colour of the base layer will appear through the upper sheet where it is not printed with the layer, to form the answer. To cause the answer to substantially disappear, a user's finger or thumb is wiped across the panel in the same way as previously described, optionally from a wipe-start region. This will separate the upper sheet and the base layer as the user's finger moves, so that the correct answer will become invisible. Preferably the correct answer is printed with a colour which is only a medium contrast with the colour of the base layer, such as a lighter grey if the base layer is a dark grey or a lighter red if the base layer is a darker red, to assist in making the answer more invisible when erased. Also as mentioned previously, an opaque pattern which will tend to obscure the answer image i.e. the colour of the base layer through the upper sheet when the answer has been erased, may be printed on to the upper sheet, for example on to the top surface, such as a pattern of dots or wavy lines or similar.

Figs 18 to 22 show a further form of appearing correct answer panel. In this form the base layer 5 is either itself formed in the shape of the answer (a positive image as shown or alternatively a negative image) such as the word APPLE, or the correct answer is printed in a contrasting colour below a layer of clear or near clear wax or similar coated over the printed answer. An upper sheet icon or indicia, which in this case is

an apple shape in negative image, is printed on the upper sneet, which is shown in the drawings printed on the underside of the upper sheet at 8 (see Fig. 22). The upper sheet icon or indicia could alternatively be a positive image.

In use when the upper sheet 6 is pressed against the backing sheet 7 the upper sheet will adhere to the base layer 5 so that the correct answer of the base layer, which in this case is the word APPLE, becomes visible through the window in the upper sheet 6 as shown in Fig. 19, the window in this case being in the shape of an apple. The correct answer panel of Figs 18 to 22 is essentially the same as the appearing correct answer panels described previously with the addition of a window in the upper sheet which is preferably a negative image window interrelated to the correct answer of the base layer.

To erase the correct answer panel so that the answer is substantially less visible or generally invisible, a users finger or thumb is wiped across the top surface of the panel, from a wipe-start region 4 if provided. This will separate the upper layer 6 and the base layer 5 as the user's finger moves, so that the answer of the base layer i.e. the word APPLE in this case, is no longer visible or is less visible through the window in the upper sheet, but the window in the shape of the apple (or any other icon or indicia) will still be visible as shown in Fig. 18.

In the sign of Figs 18, 19 and 21 the negative image printed on the upper sheet 6 is printed with an opaque or relatively opaque ink so that the upper sheet outside of the apple shaped window is opaque. Alternatively as shown in Fig. 20, the negative image on the upper sheet may be printed with a translucent ink, or with a thin layer of a conventional ink so as to give the quality of translucence or in a colour that will match the apparent colour of the base material when seen through the top layer adhered to the base layer. When the upper sheet is not adhered to the base layer the answer will appear similar to as in Fig. 18 (although the surrounding area of the upper sheet may not be quite as prominent) . When the upper sheet is "blocked in" with a blunt stylus or similar to cause it to adhere to the base layer so that the base layer answer becomes visible, the colour of the base layer will show through the translucent top sheet surrounding the window, or alternatively a colour which is a combination of the base layer colour and the upper sheet colour will be apparent surrounding the window. The edges of the window itself may not be clearly visible, as shown in Fig. 20.

Instead of being printed as a window on the upper sheet the upper sheet icon or indicia may be printed as for example a positive image to one side or above or below the area of the upper sheet where the base layer answer is visible when the upper sheet is blocked in onto the base layer. For example, the upper sheet icon or indicia may comprise a positive image of a question mark ? which is printed to one side of where the answer e.g. the

word APPLE, of the base layer is visible in one state of the panel. When the panel is finger-wiped so that the upper sheet is separated from the base layer the base layer APPLE word becomes not visible, but the question mark image on the top sheet is visible. The icon or indicia on the top sheet may be printed so as to be always visible or so as to become invisible or less visible when the state of the icon is changed, by merging into the colour of the surrounding base layer colour.

WIPE-START AREA DISCONTINUITY In all of the answer panel and correct answer panels described, the upper sheet may comprise a discontinuity in the upper sheet across a substantial portion of the upper sheet (across the direction of finger movement), in the wipe-start region or between the wipe-start region and the balance of upper sheet which extends smoothly over the base layer. This discontinuity in the top surface tends to assist in the formation of a wave or wrinkle, when a users finger or thumb is wiped across the top surface of the upper sheet from the wipe-start region, which will separate the upper sheet from the base layer.

Figs 23 to 26 show an appearing answer panel similar to that of Figs 15 to 17. A discontinuity 6a is formed in the upper sheet 6 in the wipe-start area 4a. The discontinuity is a creased region 6a or a wrinkle which extends across the panel as shown. One preferred way of forming the discontinuity is to crease two (or more) adjacent lines 6a' across the upper sheet

6 (across the direction of finger movement), for example lay scribing, pressing, or embossing the top sheet to define the long sides of the crease discontinuity 6a. Two shorter lines 6a" may be similarly formed to define the discontinuity region 6a within the region banded by the scribed, embossed, or pressed lines 6a' and 6a". Any other means or technique for forming such lines, or forming such a creased or wrinkled discontinuity may be used. It is not necessary that the discontinuity be in the exact form shown. It could be formed as a more V-shaped crease in cross- section for example. The discontinuity need not be rectangularly shaped but could be oval or triangular or hourglass shaped or of any other desired shape, again formed by creasing, scribing lines, embossing, pressing or similar.

In use a users finger or thumb is placed on the wipe- start region 4a and wiped across the top surface of the upper sheet 6 from the wipe-start region 4a including over the discontinuity or creased region 6a. This will separate the upper sheet 6 and the base layer 5 as the user's finger moves. The presence of the discontinuity 6a assists in ensuring full and ready erasure of the marker or label.

Such a discontinuity in the wipe start area may be used in any form of answer panel and correct answer panel described above.

GENERAL The answer and correct answer panels are preferably formed as a sealed unit or substantially sealed unit thereby preventing the ingress of contaminates and improving mechanical robustness and structural integrity. However, small air vents may be provided in the form of one or more pinholes or similar near the periphery of the panel such as at either end for example, which can assist in easy erasure of the product, and also as mentioned the upper sheet does not necessarily need to be fixed to the base layer about the entire periphery of the base layer so long as it is fixed along at least most of two opposite sides. The wiping action employed in use assists in redistributing the wax or other material of the base layer into any cavities formed by localised pressure during writing thus extending the life of the product.

Preferably in manufacture of the products of the invention, the upper sheet is applied to the base layer with little tension or minimal tension in the material forming the upper sheet (but without excess slack in the upper sheet) . For example, while the upper sheet may be subjected to slight tension in the manufacturing process which will take up some of any inherent elasticity in the material of the upper sheet, it is undesirable for the material to be put under such tension as will take up a significant amount of the inherent elastic extension that may be available with the material. Also, it is desirable that the upper sheet be laid onto the base layer without excess

air between the base layer and the upper sheet, but at the same time air does not need to be evacuated from between the upper sheet and the base layer.

Wherever any icon or indicia or other image, window, dot pattern, or similar is printed in manufacture of the product of the invention, for example on the top side or under side but in particular the top side of the upper sheet, it may have a clear layer laminated over the printing i.e. using trap printing, to protect the printed layer for example.

The foregoing describes the invention and preferred forms and examples thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope hereof as defined in the claims.