Tango: a framework and system for algorithm animation. The role of animation in understanding and evaluating programs and developing new programs is discussed. A framework for algorithm animation, called Tango, and a system based on that framework are introduced. Related work is reviewed, and the conceptual framework on which Tango is based is examined. The implementation of the Tango system is described. The first-fit bin-packing algorithm is animated to illustrate how the path-transition paradigm simplifies algorithm animation