Maybe I'm missing something but it seemed that even if don't use the hands the result is the same ? Edit: it only happens when both hands are directly next to the wheel. Funny how the wool grows back with a different color each time, but a bit weird that it changes color before the previous on is completely used and it doesn't fully grow back to its original size.
Presumably a potential portion of the project was programmed posing in the preferred posture for peak performances