16 step sequenced drum machine. Knob 1 controls the tempo. Knob 2 selects the instrument. The keyboard sets the pattern (first two 16ths are the first two “black” keys). The pattern displays 1 for on and 0 for off. When an instrument is selected, knob three controls volume and knob 4 controls a tone parameter. I don’t love the instrument patches, but they could easily be replaced with samples or other patches. Theres wonky code in there too for syncing to an external midi clock, and the knob then adjusts to match the beats, but I couldn’t get this to work very reliably.