NB: I originally posted this with the link pointing to the QR.rb file, which is the main code file and also a piece of Ascii art. Looks like the mods switched the link back to the main project to provide more context. But to have people looking at QR.rb first and then reading about what it does afterwards was the idea. Amazing piece of work by @hirekoke.
https://github.com/mame/quine-relay/blob/master/QR.rb