The blog just leads to https://research.swtch.com/qr/draw/, which is the demo page of the blogs [1] and [2] written by Russ Cox many years ago about putting pictures in QR codes by manipulating the error correction codes in them
Hey thanks a lot, that should be the actual link behind the submission. Very interesting technique that boils down to encode a url with a ton of carefully shaped random numbers hidden in the fragment to generate the actual art.