The Plaid Model

Outer billiards provides a toy model for planetary motion and exhibits intricate and mysterious behavior even for seemingly simple examples. It is a dynamical system in which a particle in the plane moves around the outside of a convex shape according to a scheme that is reminiscent of ordinary billiards. The Plaid Model , which is a self-contained sequel to Richard Schwartz’s Outer Billiards on Kites , provides a combinatorial model for orbits of outer billiards on kites. Schwartz relates these