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

[1]: https://research.swtch.com/qart [2] https://research.swtch.com/field

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.

That's the example url from the linked blog introducing this technique http://swtch.com/pjw/#123456789...

Source Code (Go) is here: https://github.com/rsc/qr/tree/master/qart

Messing with that demo page, it seems to manipulate the URL you put in there too adding some numbers after an anchor tag (#) at the end, rather than just error correction.

Interesting I was wondering about this, if you control the domain and web server technically you could even make a full path of arbitrary data that then redirects to the real target.

Made me wonder how easy it is to embed QR codes inside everyday images/objects without them being visible until you scan the object.

Does this mean you could make a gif which is a valid QR code playing Bad Apple?

Yes: https://www.reddit.com/r/touhou/comments/ueo304/i_played_bad...

https://news.ycombinator.com/item?id=40377122

A series of QR codes that each link to the next frame of bad apple is the logical conclusion to me