Seven red motor sirenes are hanging at a steel rope of 15 meters length. They get short impulses of power which make them produce a short, cat-like sound and at the same time the impulse energy of their motors make them move in a sudden way. These impulses are controlled by random generators.

Alternating to this state is the state of low constant power. The sirenes get just enough power to move the motor which makes them produce a soft humming.