Musical Instruments Design Let It Play musical device by Aminreza Shokouhi With Let It play when the wind blows or tree branches shake by natural factors, people can hear a melody with a random combination of notes in a particular scale, a Pentatonic scale for instance. This makes the combinations pleasant. By any change in wind properties and in branches movements' orders, infinite ear catching melodies will play. People hear what nature is composing. Let It Play has two flexible slings in order to be attached to tree branches. It has flexible solar cells on the body and electronic parts for motion sensing and power storage for night use.