Rhythm is originally the rhythm of the feet. Every human being walks, and, since he walks on two legs with which he strikes the ground in turn and since he only moves if he continues to do this, whether intentionally or not, a rhythmic sound ensues. The two feet never strike the ground with exactly the same force. The difference between them can be larger or smaller according to individual constitution or mood. It is also possible to walk faster or slower, to run, to stand still suddenly, or to jump.