Leonardo - An integrated C programming environment for reversible execution and logic-based software visualization developed at the University of Rome "La Sapienza". JFLAP, JAWAA, jeLLRap -- Visual and Interactive Tools - Tools (Java programs) for visualizing and interacting with theoretical computer science concepts. JAWAA is a tool for creating algorithm animations on the web. Opsis - A Java applet designed to teach binary search tree algorithms. It is unique in the way it combines programming, proof, and animation to enhance the learning experience. Sort Algorithms Visualizer - Applet and web site for teaching sort algorithms. Includes animation of 11 algorithms and some in-depth studies. Java Applets for Data Structures and Algorithms - Demonstrate fundamental concepts in Data Structures and Algorithms. Backtracking - A combinatorial puzzle is presented making visible the performance of a backtracking algorithm (requires JavaScript). Java Interactive Software Visualization Environment - JIVE is an object-oriented general-purpose animation system for the visualization of Java coded algorithms. Visualizations can be embedded in a Java browser or attended in a Virtual Classroom by several users at once. The Complete Collection of Algorithm Animations - A list of links to algorithm animations, primarily Java applets. The list includes an overview of each of the linked algorithms. LYDIAN - Simulation and visualization environment for distributed algorithms that provides students with an experimental environment to test and visualize the behaviour of distributed algorithms. Graph Animations with Combinatorica - Animations of several important graph-theoretic topics and algorithms.