Topobo is a 3D constructive assembly system embedded with kinetic memory�the ability to record and play back physical motion. Unique among modeling systems is Topobo�s coincident physical input and output behaviors. By snapping together a combination of passive (static) and active (motorized) components, users can quickly assemble dynamic, biomorphic forms such as animals and skeletons, animate those forms by pushing, pulling, and twisting them, and observe the system repeatedly playing back those motions. For example, a dog can be constructed and then taught to gesture and walk by twisting its body and legs. The dog will then repeat those movements.