Methods and apparatus associate a computed difference factor to avatars that are to interact with one another in a simulated environment. The virtual agent is tied to a device and not a specific instance of the OS. The system uses position information in the overlay topology for message routing between participating applications in the overly network. in addition, butadiene can be converted to monomers such as methyl methacrylate, adipic acid, adiponitrile, 1,4-butadiene, etc.