Abstract: "This report describes a variety of 3D interactive graphics techniques for visualizing programs. The third dimension provides an extra degree of freedom for conveying information, much as color adds to black-and-white images, animation adds to static images, and sound adds to silent animations. The examples in this report illustrate three fundamental uses of 3D: for providing additional information about objects that are intrinsically two-dimensional, for uniting multiple views, and for capturing a history of execution. The application of dynamic three-dimensional graphics to program visualization is largely unexplored. A videotape of these animations is available."