It’s a Nixie clock made without a microcontroller. In fact, there aren’t any logic chips in this circuit, either. As far as we can tell, the logic in this clock is made with resistors ...

Nixie tubes, while built during the vacuum tube era of the mid-20th century, still exist in a niche among hackers. It’s quite the task to get them up and running due to a number of quirks, so ...