Learn while having fun with the K'nex Education intro to simple machines: wheels, axles, and inclined planes set. This 221-piece set lets kids build seven fully functioning replicas of real-world machines (one at a time). With this fun set, kids are introduced to basic scientific concepts while creating simple machines. | K’NEX Education Intro to Simple Machines: Wheels, Axles, and Inclined Planes Set - 221 Pieces (78620)