Abstract: We propose an interactive design system for rapid crafting of planar mechanical characters. Our method combines the simplicity of sketch-based modeling with the ease of defining motion through extreme poses. In order to translate digital designs into fabrication-ready descriptions, our method automatically computes the mechanical structure that makes the characters move as desired. We achieve real-time performance by limiting the mechanical structure between pairs of components to simple building blocks that define, trim, and propagate their motion. By focusing on shape and motion, our system emphasizes the creative aspects of character design while hiding away the intricacies of the underlying mechanical structure. We demonstrate the flexibility of our approach on a set of virtual designs and physical prototypes.