Large Color Clock
A large clock that shows time by two or three large, overlapping color wheels. Each wheel is some sort of gradient with a line showing the start and end of each gradient. Those lines are the hour, minute and second hands. The wheels are at least somewhat transparent so the colors are constantly changing.
I think it would be easy to build since clock parts are easy to get. A strong enough motor would be required, and the material for the wheels has to be light weight.
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