The idea behind iterator is simple: The x-axis controls the sample playback position. The y-axis controls the repeat speed.
You can start with any of the built-in 75+ samples from over 25 artists, including Richard Devine, Parallel Worlds, Toppobrillo, Atomic Shadow, and more. You can also load your own .mp3s via iTunes.
Here’s a demo of Iterator in action:
Iterator is $3.99 in the App Store.