Ability to layer notes within one instrument

[meenie]

This is mostly for piano music, but the easiest way to explain is if you wanted to play a whole note with your thumb and then on the 2nd, 3rd, and 4th, beat of a 4/4 time signature play quarter notes with your ringer and middle fingers. So the whole note would be held over that whole bar, while also the quarter notes are layered on as well.

[ghost]

I've been learning JS for a little over a month as of now, so I'm not comfortable enough with it to try and code this myself.

To layer the notes, someone could just implement an instrumentName.back() function, that works exactly like a rest, but with a negative rhythm value. Actually, that is how MusicXML layers notes.