In behavior-based robotics (Brooks, 1999), the complexity of behavior is due to a combination of embodiment and situatedness. Embodiment is the degree to which a robot can affect its environment. Situatedness is the ability of the robot to sense its environment. As the sensors of a robot become more sophisticated, or even merely greater in number and variety, the robot will become capable of producing more and more complicated behavior provided that it is placed in an interesting environment (Braitenberg, 1984). In this context, an interesting environment is an environment in which various qualities that can be sensed are distributed unevenly.