I had fun, playing around with this and I love the look of it. Did you create the art by yourself? This is amazing!
I would love to have more control over where the marbles roll, or did I misunderstand how T-junctions and crossways work?
Glad you liked it! Yep, I drew everything myself. :)
And yeah, it's entirely random where things go (and what notes play) because I couldn't decide on a better implementation.