I have just made a small MFO NES MUX patch.

On the oscillator section, you see the "wave index" and "porta time" option. I don't really think I have to explain these, most people here probably know what they are. Wave Index just changes the pulse width.
Then, you have an LFO, with a synced frequency, controllable amplitude and start phase, and contollable start fade.
And lastly, you have an amplifier envelope. Self-explanatory, you can see what options are there.
I hope you enjoy this ! I might make more MUX patches sometime.
