rainflow is an electronic instrument that mediates the flow of time. It reimagines the traditional rainstick as an hourglass, allowing performers to explore sonic structure. 
rainflow is made of an accelerometer in a weighted casing. It is controlled with the same gestures as a rainstick: tilt and shake. The instrument is wirelessly connected to a musical engine that can operate in different modes. In one of the modes, tilting the instrument (as if shifting grains in a rainstick) scrubs back and forth through an audio or video clip. The techniques of granular synthesis are used to introduce randomness and time stretching, drawing out new sonic textures from the source material.