Genghis - iRobot
Genghis is a very classy walker created by Rodney Brooks of iRobot.
It has six legs, and uses Subsumption Architecture.
It has an array of heat sensors, and is built up with behavioural layers from a basic instruction top stand, through to walking(lifting a foot, and following with an involuntary step reflex), through to a complex hunt and prowl behaviour.
Genghis sensing behaviour is based on movement. When it senses movement, it will turn towards it, and walk towards the stimulus.