We have all see Nixie Tube clocks and at first this might seem like it is simply another. Well that is where you would be wrong. This clock is made using only tubes!

“Also cold-cathode tubes, which found use in former times gladly in ring counters (organs, etc.), were not intended. The counting stages should be developed only with completely classical flip-flop stages. The 1-second pulse should be won most simply from the frequency and be responsible for the current supply a tube power pack. For indicator decoding relays were intended at the beginning. I regarded and on the necessary number of tubes analyzed each functional module separately. From these first considerations I designed then the chassis. The following picture however already shows it with an extension at the left and right side. Whereupon I later still return.”

Via: Michael Covington