This could be a nice build to do with kids. Basically its an arduino nano on a board with 7 LEDS that is spun by a DC motor (separate power on that). I like the build and it looks pretty simple. The PCB layout is not available and I think I would put the USB end of the nano on the other side. Actually, I wonder if this could be adapted to a ESP with a bit shifter (that way you can change the working via wifi).
https://www.instructables.com/id/Rotating-LED-Display-That-Shows-Infinite-Words-POV/