I actually just put them up on the wall in my house a couple of weeks ago. Here’s a video of them in action.
There is a small flaw right now. As you turn them, one of the “nuts” holding them to the wall gets tighter on one of the biggest gear, and it makes it harder and harder to turn. You have to then turn them in the other direction to loosen it.
I have to find a way of fixing that nut in place so the gear is always loose, but held in place.