Gears turn, lifting a lever, releasing a marble, igniting a chain-reaction of learning and fun as kids design their own Rube Goldberg-inspired Crazy Contraptions! Kids will explore simple machines like never before, easily connecting them, customizing them, and repositioning them on TeacherGeek’s unique new contraption base. Just slide the machines in and out of position! Done with the activity? The bases and machines are easy to store for use year-after-year. It's the simplest way to craft the craziest contraptions!