1 - activate the levers to turn notes on/off 2 - when you like the arpeggio add the chords with the '+' button 3 - click play to start sequence of chords 4 - green flag to start over
It's still very unfinished (and a little stuck here and there) but I think you can play with this... I had seen many examples from the studio and I had already used lists in a couple of 'unstuck' projects so I was running short of new ideas... I saw @giuluck97's project that got me started on this https://scratch.mit.edu/projects/412088642/ (thanks for the idea!) Now it's reeeeally too late, and I'll post it as it is...so just be patient :-)
