I kinda want to see a riff generator, searchable by chord base/tonality, time signature, and length. Also a scale exercise generator. Lot of space to explore in

I kinda want to see a riff generator, searchable by chord base/tonality, time signature, and length. Also a scale exercise generator. Lot of space to explore in terms of permutations. I seem to recall some research on probability of usage of a particular set of notes/chords based on information entropy but I can't find that anywhere.