Here's a closeup:
I wanted to make my own from scratch so I started building it. When I had the frames mounted on the spindle I wanted to test it and since I didn't have a box yet, or any other plans for a crank or a motor, I mounted it on the drill to get a smooth rotation. The drill seemed like the easiest thing that was lying around at the moment.
This flip box isn't quite finished. You can follow its progress on Tubon's Instagram.