TOPLAPapp is a free application for the Apple iPad that uses a sonic puzzle as the interface for a virtual machine for sound synthesis.
If also has one of the strangers user interfaces ever created for a synthesizer.
This machine accepts a few valid instructions represented by the letters T, O, P, L, A, and p. You control TOPLAPapp by placing each command letter within a grid, along with setting some associated parameter sliders.
The machine rushes through the instruction set to create output sounds, which are usually of a somewhat noisy character, hopefully interestingly so.
The historical antecedents include instruction synthesis as pioneered at the Institute of Sonology in the 1970s, and the live coding movement, of modifying a running program as it acts.
Note: Developers warn "This app is intended for those interested in more experimental sound art: don't download unless you are open to stranger computer music sounds".
Pricing and Availability
TOPLAPP app is a free app and is available now for the iPad, iPhone and iPod touch.