The Chebyshev Walking Machine
The Chebyshev linkage is a mechanical linkage that converts rotational motion to approximate straight-line motion. It was invented by the 19th century mathematician Pafnuty Chebyshev who studied theoretical problems in kinematic mechanisms.
One of these linkages is shown above. It is called the Chebyshev walking machine. Notice that the mechanism seems to reproduce the legs of an animal. Click the Play button to start the animation.