The Hungarian composer György Ligeti composed Poème Symphonique for 100 Metronomes in 1962, during his brief acquaintance with the Fluxus movement. The piece requires ten “performers,” and most of their efforts take place without the audience present. Each of the hundred metronomes is set up on the performance platform, and they are all then wound to their maximum extent and set to different speeds. Once they are all fully wound they are all started as simultaneously as possible. The performers then leave. The audience is then admitted, and take their places while the metronomes are all ticking. As the metronomes wind down one after another and stop, periodicity becomes noticeable in the sound, and individual metronomes can be more clearly made out. The piece typically ends with just one metronome ticking alone for a few beats.
Here is the score for the work: