Discover unexpected ways to turn common materials into crafty contraptions that range from surprisingly simple to curiously complex. In vivid color photos, you'll be guided to create slingshot rockets, unique catapults, and even hydraulic-powered machines. Whether you build one or all 19 of these designs, you'll feel like an ingenious engineer when you're through. Best of all, you don't need to be an experienced tinkerer to make any of the projects...