An overview of the ANIMAL rapid prototyping system is presented. ANIMAL is designed to support research in real-time musical signalprocessing and event processing. ANIMAL allows users to draw pictures which define complex data objects. These pictures can function as animated real-time controls. Dynamic collections of these graphical objects cau1 be created, making it relatively easy to design graphical event list editors, synthesizer interfaces and, in general, any interface involving visualization and manipulation of quantitative data applied to colleclions of discrete objects.