Reich came up with the concept while working at the University of Colorado. He was swinging a live microphone in the style of the cowboy’s lasso, and noting the produced feedback, he composed for an “orchestra” of microphones.Three or more microphones are suspended above the speakers by means of a cable and stand. The microphones are pulled back, switched on, and released over the speaker, and gravity causes them to swing back and forth as pendulums. As the microphone nears the speaker, a feedback tone is created. Different lengths of cable will swing at different speeds, creating an overlapping series of feedback squeals. The music created is thus the result of the process of the swinging microphones.