Take the grooves of a record, completely unwind it, and put it in a straight line. If you then run a stylus along that groove at a constant speed, the recording will get faster and faster even though the stylus is moving at a constant speed. This is because the record had it's grooves cut in a 'spiral'. meaning the outer grooves are larger in circumference than the inner grooves.
This proves that the geometry of the groove can effect the pitch. If proves that if the groove were in one streight line it would behave differently if it were then wound into a spiral. And that's the idea behind it, to take what is generated at a constant rate, wrap it into a spiral, and rotate it. This has the opposite effect, because rather than recording in a spiral then unwinding it, you're recording in a streight line then winding it into a spiral. It's this spiral that causes one aspect of the oscillators behaviour.
The other aspect is that there's a stylus for every groove in the spiral. So if the density of the spiral is low, say only six turns, then you get 6x stylus to output the sound simulatneously. If the spiral is super-dense having something like 120 turns, then you get 120x stylus outputting the sound simultaneously, cause like I said, the oscillator has a stylus outputting sound from each groove simultanously.
Now you take those two aspects, add them together and you get the Rotating Oscillator. Because due to the time-shifting caused by it being a spiral, it means you can change the characteristics of the harmonics by altering how close together and far apart the grooves are as they rotate. For example, if you modulated the groove spacing across it's surface by using a sinewave, the density of the grooves would get progressively closer and far apart across the surface. Remember, you have to draw a virtual line from the outside of the circle to the center of the spiral, and no matter how many stylus you generate due to groove density, they all sit on that same line.
If you were to do this with a real record, the sound would be a mess, but the sound from each groove would sound as if it was playing at the same speed. That is not the case with the Rotating Oscillator, simply because the sound was not made in a spiral formation, but rather a streight line that was then wound into a spiral. This means that the pitch will differ from each stylus that is outputting sound, therefore giving you control over the sound, over the harmonics, over the phasing etc.
This is what makes me think that such an oscillator would totally rock at string instruments when modulating the groove density across the width of the virtual playhead line. I can imagine it would also work well for air/breath in vocal synthesis, stuff like that.