Lego Chain Reactions + Lego Crazy Contraptions, Both Klutz Lego Books and Pieces Set of both Klutz LEGO kits: 2 books and LEGO pieces kits! Design and build amazing moving machines - teach your bricks new tricks! Chain Reaction Kit has 33 LEGO unique pieces, 6 plastic balls, string, paper ramps and other components Crazy Contraptions Kit includes 105 LEGO bricks, gear & axle, all you need to create 16 unique projects ...plus two crytal clear photo illustrated step-by-step guide books to show you how!