still working on https://stringscales.com - fun sideproject to visualize guitar scales on a configurable fretboard, with interactive note highlighting to a backingtrack.
The backingtrack is what I'm actively improving right now. It's just a pad running now, but it will turn into a full track with bass/drums/piano/... and will feature a comprehensive chords based editor so you can add and save your own progressions with a logged in account.
Does it let you visualise quarter tone fretting? (Or is it just me who's obsessed with Angine de Poitrine right now?)