• over_clox@lemmy.world
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    3 days ago

    Did you know that you can halftone dither two different but same size QR codes on top of each other?

    I wish I had a link to the article handy, but yeah I’ve tried that myself and it totally works! You basically get a 50/50 chance of one or the other code scanning. It’s literally two QR codes in one!

    And no, that’s not some new special QR code format either, it’s basically taking advantage of the nature of the scanners plus the built in error correction.

    • fulcrummed@lemmy.world
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      2 days ago

      What’s a use for an ambiguous QR code panel where you can’t predict which of two codes may be scanned? I’m struggling to come up with anything that makes sense where the mechanism potentially slightly favours one or the other depending on the scanner/ tones used.

      • over_clox@lemmy.world
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        2 days ago

        The two QR codes could be totally related, like two different versions of a rickroll, or two different versions of bad apple.

        You just never know exactly which one you’re gonna get…

        Hint, in my experience testing that, it partly depends what angle you’re holding your device when scanning such combo QR codes.