Polyominoes

　　Polyominoes will delight not only students and teachers ofmathematics at all levels, but will be appreciated by anyone wholikes a good geometric challenge. There are no prerequisites. Ifyou like jigsaw puzzles, or if you hate jigsaw puzzles but haveever wondered about the pattern of some floor tiling, there is muchhere to interest you. A polyomino is a shape cut along the linesfrom square graph paper; the pronunciation of polyomino begins asdoes polygon and ends as does domino. Tilings, also calledtessellations of mosaic patterns, are older than civilizationitself. Tiling with polyominoes provides challenges that range fromthe popular jigsaw-like puzzles to easily understood mathematicalresearch problems. You will find unsolved puzzles and problems ofboth kinds here. Answers are provided for most of the problems thathave known solutions. It is only fair to repeat here the warningstated in the preface to this book, 'Playing with polyominoes canbe habit forming.'