Underactuated Robotics
Another version of this course (I <i>think</i> it was an OCW version on YouTube.) had a video of a fish holding position in a stream. There was an obstacle in the stream, and the fish swam up into its wake to save energy. Neat. Then they showed a video of a dead fish being towed through a simulated stream by a line. It exhibited "swimming" behavior that could be dismissed as just flapping in the current right up until the <i>dead</i> fish swam up into the lee of the nearby obstacle for shelter.<p>It's amazing how much adaptation and complex behavior can be embedded into an underactuated system. A fish's dead body "knows" how to save energy when swimming against a current!