Two-way jigsaw puzzle

Abstract

A jigsaw puzzle and method of manufacture wherein incongruent pieces can be assembled into distinct interlocking arrangements to produce at least two different, often unrelated, pictures from markings on the upper surface of each piece.

1 . A puzzle comprising: a plurality of pieces each having color, pattern, or color and pattern markings upon at least a first side, wherein at least two different said first side color markings, pattern markings, or color and pattern markings are present in the completed puzzle, each piece further comprising at least one engaging portion for allowing the piece to temporarily interlock with a corresponding engaging portion on an adjacent piece to form a connector pair, the pieces being shaped such that they interlock in a first arrangement defining a first surface upon which the different markings on the first side form a first mosaic image, and interlock in a second arrangement distinct from the first, defining a second surface upon which the different markings on the first side form a second mosaic image, wherein a majority of the pieces are incongruent and the puzzle comprises a plurality of connector pairs of different shapes. 
     
     
         2 . The puzzle of  claim 1  in which at least one piece has at least three engaging portions, said engaging portions meeting three different adjacent puzzle pieces on at least three points, said points being positioned with rotational symmetry about a center point equidistant from said points. 
     
     
         3 . The puzzle of  claim 1  in which at least one piece has four engaging portions, said engaging portions meeting four different adjacent puzzle pieces on four points, said points having fourfold rotational symmetry about a center point between said meeting points. 
     
     
         4 . The puzzle of  claim 1  in which a first piece has a marking upon a first side that is essentially the same in appearance as a marking upon a first side of a second piece. 
     
     
         5 . The puzzle of  claim 1  in which a first piece has a first side marked with a solid color, a second piece has a first side marked with said solid color and a third piece has a first side marked with a different solid color. 
     
     
         6 . A method of manufacturing a puzzle comprising the steps of:
 (a) defining a plurality of pieces, each having at least a first side with markings thereon, such that at least:
 (i) one piece has color, pattern, or color and pattern markings on at least a first side such that the appearance of the markings is essentially the same upon rotation of the piece; or 
 (ii) at least two pieces have color, pattern, or color and pattern markings on at least a first side of each such that the appearance of the markings is essentially the same upon exchange of the two pieces, 
   (b) assigning each piece to a primary position in a primary arrangement;   (c) assigning each piece to a secondary position in a secondary arrangement;   (d) assigning engaging portions to each piece such that each piece fits into its primary position in the primary arrangement and fits into its secondary position in the secondary arrangement;   (e) counting the number of ways in which interlocking pairs of pieces can fit together;   (f) reducing the number of ways in which interlocking pairs of pieces can fit together by reassigning pieces to different secondary positions in the secondary arrangement and repeating steps (d) and (e);   (g) repeating step (f) until a satisfactory minimum number of piece fits is achieved.   
     
     
         7 . A method as claimed in  claim 6  wherein step (f) comprises the sub-steps of:
 (a) randomly selecting a first piece; 
 (b) randomly selecting a second piece: 
 (c) if the first piece and second piece are the same piece, which can occur because the selecting process assumes replacement of the first piece before the randomly selecting a second piece takes place, assigning that piece a random rotation that maintains the general appearance of markings on its first side; 
 (d) if the first piece and second piece are different but have substantially equivalent markings on their first sides, exchanging the location of the two pieces and assigning each piece a random rotation that maintains the general appearance of markings on the first side of each; 
 (e) repeating steps (a) through (d) with the same piece pair with different rotations or by using different pairs; 
 (f) continuing step (e) with a general tendency of reducing the probability of the number of ways in which interlocking pairs of pieces can fit together.