The simulator of the MAC timing behaviour is developed under Ptolemy, a visual programming development environment of the univerisity of Berkeley in California. It allows the user to choose a domain, in this case the discrete event domain, and 'cut and paste' an application from a library of components. Ptolemy adds a scheduler that governs the event order and compiles your application to C code. 

The layered structure keeps complex simulators easy to handle, as components can be developed and tested independently. By clicking the figure below one can zoom in to one of the composing stars.