Avid puzzle mavens will spend hours slicing and dicing these wildly-hued brainbusters. That's because so many of the problems deal with dissecting geometric shapes--polygons, hexagons, squares, even a chessboard--into congruent parts or figuring out how the split parts would fit back together again. For example, to complete "Exploding Star," solvers have to copy the star in the book, cut it carefully into 12 colored pieces, and then rearrange them into four identical replicas of the big star. But this tough but fascinating collection has lots more to offer: there are tangram paradoxes that offer a new spin on the ancient Chinese game, mathematical conundrums dealing with weight and gravity, Egyptian rope puzzles, and host of other complex challenges.