Artificial Life Environment (ALiEn) is a simulation program based on a specialized 2D physics and rendering engine in CUDA. Each simulated body consists of a network of "smart" particles that can be enriched with higher-level functions, ranging from pure information processing capabilities to physical equipment such as sensors, actuators, weapons, constructors, etc. To orchestrate the execution, a token concept from graph theory is utilized. The bodies can be thought of as small machines or agents operating in a common environment.