Physicles, is a free MIDI app.
This is a physics-based AU MIDI plugin collection – although right now there is only one plugin, Bouncy. I plan to create at least one more plugin (Sandbox), although it will take a while.
So, what is Physicle Bouncy? This is a particle emitter AUv3 MIDI app that is heavily influenced by Caelestis, with a little dose of PHYsynth. In more detail: in this app, various balls bounce within a (rotating) box; and MIDI messages are generated whenever a ball collides with the side of the box. All balls and the border follow the laws of physics (although with no gravity and perfect elasticity), and their velocity and direction can be changed individually. Besides, it is possible to “play” the AU, by changing the notes played by the box or by the balls upon collision by using the host’s piano. With this it is possible to play chords using interesting rhythms o:) . Besides, I have used some of the conventions of the Rozeta suite that I think all AU MIDI apps should have, like the possibility to change the current playground using the host’s piano (keys C1-C2)
Physicles in the appstore https://itunes.apple.com/app/id1409156444