Then I added charts for other instruments I mess around with: piano, cello, alto recorder.
There's a complexity toggle to go from basic harmony to extended/experimental stuff.
It's honestly still mostly a toy, but I thought other people might be interested in playing with it. Source is on github, so it's easy enough to run locally and fork.
https://github.com/aleshh/gtr-scales
Show HN: I made a tool for learning scales, chords, and how to combine them
projects.alesh.com