Both. But I've passed on the site to musicians and non-musicians alike - everybody loves is.
The midi capability is stunning and ability to choose tonalities can be 'just left to play', or used as an inspirations for the basis for repetetive or repeating motives: repetition, and an element of predictability - both based in a predictable tonality is what most people seek in what they call 'music'.
Trapping the balls may give you something more approaching 'music'.
Changing the root note, also.
And the 'mode', too.
