This clock is kind of difficult to explain. The basics of the clock are two
concentric rings of LEDs, the inner ring representing the tip of the hours hand
and the outer one representing the tip of the minutes and seconds hand. A
picture certainly helps, so best to look at this first.
YouTube video of the clock in action For scale, it is 14 inches on a side.
That was just a personal project, it wasn't rational from a cost perspective.
The TAPR folk asked me to write up an article for it, this is the web page with
the support information.