here it is
Thanks for the write-up. This is the portion that I struggled with understanding the most (especially difficult if you're not working on a full-blown matrix):
gap colour, as per this chart:
1st colour = White keys
2nd colour = Black keys
3rd colour = White key depressed
4th colour = Black key depressed
5th colour = gap between white keys (this isn’t necessary)
I also found it very helpful for studying the conversion-chart between nodes and MIDI# (which you've also included in your write-up).