"Polypod is a reconfigurable module robot. It’s made up of two types of modules called segments and nods. Segments are two degree freedom modules with two motors, force and position sensing and a microcomputer on board. Nods are [inaudible] shaped housings for batteries. Segments may be mounted parallel to each other or they may be mounted perpendicular to each other. Modules may also attach on any face of a nod. Simple locomotion gaits are statically stable gaits that move along a straight line..." See the whole transcript at Introduction to robotics - Lecture 06