Source: https://ena.computer/

Unfortunately we have not been able to find out, who the creator of the following project is. So we can not credit this person. Nevertheless we did not want to leave the ENA Computer out of this issue.

What Mrs. or Mr. I-have-too-much-time-and-long-time-therefore-I-just-do-it presents here, is an achievement in a class of its own. Nothing particularly to learn here, but seeing a fully functional, programmable and Turing-complete computer made from old-school tubes on modern day PCBs is not something, you would see every day.

You can read about the project and the technical details here. I personally liked the Nerd-Human <-> Human-Nerd Dictionary ... Should it spark like that? means.. I'm really scared.

Hats off to the creator! Seriously.