TRACK is a kit to interactively construct environments that trace the execution of methods and the flow of messages between SMALLTALK-80 objects. It enables the user to set up traces by means of direct manipulation. This is done by placing obstacles between icons representing specific classes and instances much in the way a jumping course is set up. TRACK may be used to generate multiple visualizations of programs which may be concurrently run. It is a browsing and debugging tool as well as an algorithm animation tool. TRACK is tightly integrated with the standard tools of the SMALL- TALK-80 programming environment.

It has been argued for a long time that the representation of a problem is of crucial importance to understanding and solving it. Equally accepted is the fact that the human visual system is a powerful system to be used in information processing tasks. However, there, exist few systems which try to take advantage of these insights. We have constructed a variety of system components which automatically generate graphical representations of complex structures. We are pursuing the long-range goal of constructing a software oscilloscope which makes the invisible visible. Our tools are used in a variety of contexts: in programming environments, in intelligent tutoring systems, and in human-computer interaction in general by offering aesthetically pleasing interfaces.