This paper describes the successful implementation of an animation protyping tool for the development of concurrent software. It allows the designer to model such systems in graphical terms, while also connecting it transparently to the underlying scheduling functions. The model may be exercised to evaluate and predict task performance as system parameters are varied - number of tasks, task interaction, execution times, periodicy, deadlines, task statistics and scheduling policy. At the present time the animator can be successfully applied to first-cut descriptions of the concurrent software. It has, however, been developed primarily as a research tool. For more general use it needs to be refined and extended.