Makes me wonder what the difference, in definition, is between a sequencer and a synthesizer? Is this really a synthesizer, or is it really a sequencer?
The linked project is both. A synth makes sounds, and a sequencer controls the sound over time usually with note on/off data. This sequencer has 4 steps before looping back to the beginning. To simplify, think of a sequencer as the music box drum and the synth as the tines in a music box.