In Bali there is an ingenious irrigation system in which large pieces of bamboo on hinges fill up with water from a stream then flip over, spilling water into the rice fields. As each tips back it produces a hollow tapping sound and one may hear amid the continuous bubbling of water a delicate and irregular recital of taps from fifty or more of these little water mills in operation at once.

Schafer, Murray R, The Soundscape- Our Sonic E…, loc. 840