The generator creates two separate QR codes with high error correction (Level H) and combines them into a single image using pixel splicing. Each cell that differs between the two QR codes is split in two, creating a pattern that can be interpreted differently based on the scanning angle.
I've long wished hyperlinks would permit multiple hrefs. Hypertext could be more sophisticated.
Multi-link QR codes could be practically useful, provided an interstice appears with the URLs and allows a person to follow any of them or all of them.
They did. I think the idea with XML based hypertext was to have links that are star-shaped with potentially multiple sources and potentially multiple targets and the location where the link is defined completely independent from any sources or targets.
One application would have been that people publish link collections and you could e.g read HN with the links I created.
There was a proposed standard for this but its name escapes me for the moment.
Of course all of this never went farther than XHTML where it took a sharp turn into a different direction.
This is interesting and sets off a bunch of ideas. It might be fun to generate a printed version that can differently depending on how it's lit, either red/green or tricks with pwm'ing LEDs...
Not all questions have an answer that will satisfy you.
In this case, it probably exists because it's technically interesting, and for no other reason.
Although I can totally image a roulette style game played by people who like that kind of thing: one link leads to something nice like puppy photos, the other leads to something disgusting.
Readit News
(https://github.com/zacharyreese/DualQRCode)
The generator creates two separate QR codes with high error correction (Level H) and combines them into a single image using pixel splicing. Each cell that differs between the two QR codes is split in two, creating a pattern that can be interpreted differently based on the scanning angle.
Multi-link QR codes could be practically useful, provided an interstice appears with the URLs and allows a person to follow any of them or all of them.
One application would have been that people publish link collections and you could e.g read HN with the links I created.
There was a proposed standard for this but its name escapes me for the moment.
Of course all of this never went farther than XHTML where it took a sharp turn into a different direction.
XLink? It supports a feature known as extended links, which seems similar to what you're describing.
https://en.wikipedia.org/wiki/XLink
https://news.ycombinator.com/item?id=42809268 - A QR code that sends you to a different destination – lenticular and adversarial (2025-01-23, 76 comments)
Wouldn’t it be easier to just have the link the QR code points to show a language picker?
In this case, it probably exists because it's technically interesting, and for no other reason.
Although I can totally image a roulette style game played by people who like that kind of thing: one link leads to something nice like puppy photos, the other leads to something disgusting.