Here’s an interesting project from several years ago. The clock design itself isn’t too noteworthy, but the construction is definitely inspired. You’ll notice that there is no breadboard or PCB, the frame actually is the circuit. The tubes he’s using are Numitron tubes, which aren’t as high voltage as Nixies or even VFDs. This means that there is only 12V maximum going through the exposed rails. He discusses some possible future upgrades such as LED or Nixie or VFD, but since this project is a few years old, who knows if he is still working with it.