Music Machine 3 is based on a piano duet that I composed some time ago.
The original piece had one person playing a repeating 24 bar pattern whilst the other player made selections from 14 small cells of music. The decisions about how the piece worked were made entirely by the second player (when to play, when not to play, when to repeat a cell continuously, when to play it just the once and so on).
This process is replicated in the Music Machine 3. The play button starts the 24 bar repeating pattern (see below), pressing any of the other buttons will play the numbered cell once or repeat it until it is stopped. (The cells are shown below). Once a cell is repeating it is not possible to play another cell until the first one is stopped. Similarly there is a short delay once a single cell button has been pressed to allow that cell to finish before another can be played. (If you're very quick you can get a tiny overlap, my intention was to make it possible to play one single cell immediately after another and there was a necessary compromise on the timing of this, particularly when the small cells are selected).
The 24 bar pattern will run indefinitely until stopped by the user.