Algorithm animation has a growing role in computer-aided algorithm design, documentation, and debugging, because interactive graphics is a richer channel than text for communication. Most animation is currently done laboriously by hand, and it often has the character of canned demonstrations with restricted user interaction. Animus is a system that allows for easy construction of an animation with minimal concern for lower-level graphics programming. Constraints are used to describe the appearance and structure of a picture as well as how those pictures evolve in time. The implementation and support of temporal constraints are substantive extensions to previous constraint languages that had only allowed for the specification of a static state. Use of the Animus system is demonstrated in the creation of animations of dynamic mechanical and electrical circuit simulations, sorting algorithms, problems in operating systems, and geometric curve drawing algorithms.