Before you tell me "I can see you" I know, and I don't mind. This was the output of a circuit I built in early 2018 that was a relay that had it's power running through the normally closed gate, causing it to oscillate. I was running a 12 volt relay on about 3 volts, so the amplitude was rather low.

I no longer have the oscilloscope shown here (I had to get rid of it when I moved last October) but it was an old Tektronics oscilloscope that I think was from the 70s. I didn't have any coaxial probes for it so I kind of just had mashed wires into the coax connectors to probe it.

As you can see, the waveform looked roughly like a sawtooth wave and also seemed to be rather noisy, so if I were to use the voltage in music, I would have ran it through a low pass filter or a limiter to clean it up a bit.