The other key idea in TeaTime is our approach to resilience and fault tolerance. Most large scale distributed virtual environments are quite difficult to handle because at any point in time some elements may become disconnected and other elements may be dynamically added. We recognize this issue in the Croquet object model - each object is responsible for maintaining sufficient information to recover from system disruptions. The key idea in TeaTime is that the state of objects evolves through a distributed two-phase commit protocol. Behaviors of all objects that influence each other are first computed, contingent on completion of all dependent object behaviors, and then those behaviors are atomically committed. If the behaviors are not completed in time, all contingent calculations are undone by the individual objects.