Check out this smart shelving system driven by an Arduino and using LEDs, which serves as a clock.

The Arduino uses latitude and longitude to help decide when to click on the lights, so it's incredibly accurate. Otherwise, the build just includes an on/off switch, a Tiny RTC, a time adjustment ...

If you are considering purchasing a Nixie tube clock kit you may be interested in a new Arduino project published by Doug Domke to the Hackster.io website ...