To be totally honest with you, I wanted to post a Flashback but the tutorial of this App is so easy to do that I changed my mind and post it as a New Post. Another reason for this change wasthat this App has not be updated since its released. September, 23th 2017 and will be no more compatible with the new iOS.
So, Concierto Para Piedra #0 is a 3 voices Noise Machine for Free. 3 oscillators. The first one is a Wavetable oscillator with a wave drawing area. The second one a Cosine wave oscillator and the last one a Sawtooth wave oscillator. Unfortunately no Audiobus or IAA compatibility and sure, because it didn't ’exist at this time, no Audio Unit feature. The generated sound is cool, the App very well done and totally Free without ads. So a big thanks to the developer! A very good little Noise Machine!