Additionally, for fun and clarity, we used red, green, and blue LEDs for the three rings, making each shadow hand of the clock a different color. Each ring has 12 LEDs, and the 36 LEDs are efficiently multiplexed by an AVR microcontroller that also handles the timekeeping part of the project.
— It’s Trippy Time!: The Bulbdial Clock – Geekologie

It’s pretty, but I would imagine you’d need to have it somewhere special, right?  like out of the sun special?  which I guess is pretty much anywhere I spend more then 30 minutes, but I digress…