jigsaw puzzle is a tiling puzzle[puzzle?:jigsaw puzzle] that requires the assembly of numerous small, often oddly shaped,
Most jigsaw puzzles are square, rectangular, or round, with edge pieces that have one side that is either straight or smoothly curved to create this shape, plus four corner pieces if the puzzle is square or rectangular. Some jigsaw puzzles have edge pieces that are cut just like all the rest of the interlocking pieces, with no smooth edge, to make them more challenging. Other puzzles are designed so the shape of the whole puzzle forms a figure, such as an animal. The edge pieces may vary more in these cases.
Since the earliest days of jigsaw puzzles the manufacturers have constantly endeavoured to create new cutting styles that differentiate their work. Even among modern, mass-produced puzzles there is considerable variation in the size, shape and intricacy of individual pieces.
