MIDI Thru based on 5x5 MIDI board for teensy 4.0
the MIDI board is: https://www.tindie.com/products/deftaudio/teensy-40-midi-breakout-board-5in-5out-usb/ added is a bit of code for WS2812 on one of teensy's 4.0 serial ports so that we see what ports beeing used.