Four-operator FM synthesizer in SuperCollider

So a while back I decided to learn SuperCollider for fun. I thought the best way to start would be by creating something I was already familiar with so I could focus on learning SuperCollider and let my experience guide the thing I was building. I like FM synthesis and have some knowledge of how it works, so I thought this would be a good topic to use to explore SuperCollider. The result thus far is a headless (i.e. no graphics), monophonic, four-operator FM synthesizer that can be controlled via MIDI (it even responds to velocity!) Up next I think I'll be working on implementing polyphony or a GUI to control individual operators. In the meantime, feel free to get a copy of the source code.