Abstract: Demonstrating how the digital computer works is beneficial for physics and computer science education. The clearer the way the computer is presented, the better. Most lucid understating one obtains from observing how a computer based on relays works, but this technology was also used in the first working digital computers, constructed during World War II. Flashback in history to computer pioneers is obligatory and should not be obviated, like the common and contemporary practice turns out to be.
       Today in Bulgaria an educational digital computer, based on relays, was invented. And though the world holds about a dozen of such computers, mainly placed at universities, the Bulgarian BRC4 is unique for it was realized using bistable relays. BRC4 may be observed at Faculty of Physics, Sofia University by anyone, who wants to touch the history, to travel in the dark years of the most dreadful war, but also to feel the spirit of time – a moment in 1941 when Berlin was resounded with the clicking rhythms of a new age