The stylus in a groove vid is really interesting but it's also pretty contrived (it had to be). As stated above, the stylus isn't moving at 33.3rpm - in fact it isn't moving at all except by a tiny amount between each still - it's loads of still photographs stitched together to give the impression of movement. Also, the stylus isn't held by a tonearm with a counterbalance weight - it's held in a much more fixed relationship to the record than in a real arm. It's all clearly explained in the video - still very good though.