Water tube clock

A standing glass tube with the inner wall shaped as 12 pockets. Starting from 12 o'clock, water level in the tube will gradually drop, and when reaching 12 o'clock again, internal pump would bring the water level back to top. Well, you won't know what is the precise minute, but as a cool clock it serves well.

Don't ask me how to tune this clock. I am not the manufacturer.

Image will come soon.