it appears to me that the sled sits stationary and the movement of the sandpaper belts moves the edge sandpaper belts which turns the piece-- am I right? If so, that is excellent "thinking out of the box".
This is one of those items that, now that the idea is out of the bag, could probably be duplicated fairly easily.
I for one will be sure to purchase it as the inventor deserves credit (and money), in my opinion, for coming up with such a revolutionary idea.
Well done indeed-
Lawrence