Walk cycles

In animation, a walk cycle is a sequence of frames representing a (usually human) walk movement. Walk cycles are important, because when a walking person appears in an animation, the walk cycle simply can be looped over and over, without having to animate each step again.

here exist many techniques to create walk cycles, for example in pixel art and 3D computer graphics. Different poses can be modelled in a 3D modeller, and frames in between interpolated. Or they can be hand drawn, using techniques like rotoscoping.
For a human walk cycle, poses like passing point, high point, contact point and recoil point can be identified as important frames defining the walk (For example in [1]).
Besides the apparent move of the legs, many more details are necessary for a convincing walk cycle, like arms, head and torsion of the whole body. Also the bottoms of the feet must squash slightly, meaning stretch out, when the pressure of the body is placed on them.