The world of Virpets is highly dynamic; even, if you will, modular and extensible. All data pertaining to a specific model is kept in its Virtual Puppet Mapping. All data pertaining to a particular scene is kept in a Stage Scene File. Last but not least, all data pertaining to a specific mapping of models to their controllers, as well as the scene for them, is kept in a PuppetMaster Setting File. The files are written in XML and have Document Type Definitions (DTDs) files as well. Basically, that means that any file written that is validated by the definition test will work in our programs.