Spent yesterday playing with Sonic Pi on my Pi4, and connecting it to my Arturia MatrixBrute. Making better progress in figuring out how to use the two together, and this piece shows the collaboration between the two.
I have to say that I am most impressed with the performance of Sonic Pi 3.2dev on a 4Gb Pi4.
I have put a sound recording on SoundCloud here and also produced a video showing the system in action.
If you are interested, the code is on my gist site here