Kinetic Sketch-Up is a system for prototyping motion and kinetic transformability into interfaces. A series of actuated modules allow users to embed programmable actuation into tangible interfaces, dynamically coupling digital information with self-reconfigurable structures. Modules in the systems combine varied materials and technologies for actuation creating different forms of motion. This provides a method to prototype perceptual qualities which motion can elicit in the design of an interface: drawing our attention, providing physical feedback, and conveying information through physical change. As interaction design begins to incorporate many of the interaction principles of robotics, the system provides a new design tool and vocabulary for motion construction in the emerging areas of transformable products, environments, and architecture.