Simon writes open source (Eurorack) sequencer software for (mainly) open source hardware. See:
SimonSaysSeeq for Norns (Lua, Norns)
SimonSaysSeeq for Bela Salt (C++, Bela)
SimonSaysSeeq for 1010 Music Euroshield (C++. Arduino)
SimonSaysSeeq for Betweener (C++, Arduino)