4 ms·

If I recall correctly the maximum binary data you can fit in the largest QR code is 2,953 bytes. This C compiler can fit on a qr code.

kibwen 6y ago
True, although "the largest QR code" is substantially more dense than most people have ever encountered: https://en.m.wikipedia.org/wiki/File:Qr-code-ver-40.svg https://en.m.wikipedia.org/wiki/File:Qr-code-ver-40.svg . People might not realize that QR codes scale up and down very gracefully; most QR codes that people have ever seen probably encode less than 80 bits.
- gregsadetsky 6y ago
  Reminds me of a project a friend and I took part in, sending each other source code via postal mail. I ended up sending a QR code printed on film negative [0] to pack about 1k of bytes. Bellard's code is way more "information-dense" of course..! :-) [0] https://greg.technology/img/postal-codes.jpg https://greg.technology/img/postal-codes.jpg Edit: incredibly, pointing the iPhone camera app at the low-ish resolution photo of the QR code above works -- the QR code does decode. That's crazy.
  - igravious 6y ago
    Hiya, how did you print these on negative film?
    - mirekrusin 6y ago
      You drill a hole in lead plate, take uranium rock, rasberry pi and...
    - gregsadetsky 6y ago
      In Montreal, the really really great people at Borealis [0] made it extremely easy. I sent them a 300 DPI file by email, and they printed negatives from those files in a few days. Each negative cost about $8 to print. Finding a lab that did this online was pretty difficult at the time. If others have recommendations -- please chime in! Otherwise, I would strongly recommend considering Borealis (who I'm sure can ship the negatives by mail -- otherwise reach out and I can facilitate the mailing as I live here ha) [0] http://www2.borealislab.qc.ca/borealis/en-home http://www2.borealislab.qc.ca/borealis/en-home
  - orthoxerox 6y ago
    This reminded me of Richard Feynman and his first wife driving military censors bonkers by sending each other puzzles.
    - gregsadetsky 6y ago
      That's an incredibly kind comparison. Thank you! Do you have a reference where Feynman talks about this? I'm finding this [0]: "Arline entered the nearby Albuquerque sanatorium, from where she wrote him letters in code — for the sheer fun of it, because she knew how he cherished puzzles, but the correspondence alarmed the military censors at the laboratory’s Intelligence Office. Tasked with abating any breaches to the secrecy of the operation, they cautioned Feynman that coded messages were against the rules and demanded that his wife include a key in each letter to help them decipher it. This only amplified Arline’s sense of fun — she began cutting holes into her letters, covering passages with ink, and even mail-ordered a jigsaw puzzle kit with which to cut up the pages and completely confound the agents." [0] https://www.brainpickings.org/2017/10/17/richard-feynman-arline-letter/ https://www.brainpickings.org/2017/10/17/richard-feynman-arl...
      - 1986 6y ago
        He talks about it in more depth in Surely You're Joking, Mr Feynman, in the "Los Alamos From Below" section
  - guerrilla 6y ago
    Why were you doing this?
    - gregsadetsky 6y ago
      It was an art project -- called "Postal Codes" -- where an artist friend and I would correspond by creating sketches (typically using p5.js or three.js) and sending them by "snail" mail. There is a bit more information here [0], here [1] and here [2]. [0] https://www.instagram.com/p/B9MhMzKHVxJ/ https://www.instagram.com/p/B9MhMzKHVxJ/ [1] https://www.instagram.com/p/B7wL7MKly3k/ https://www.instagram.com/p/B7wL7MKly3k/ (description in Spanish and then English) [2] https://github.com/gregsadetsky/postal-codes https://github.com/gregsadetsky/postal-codes (project description, "rules", and source code)

kibwen 6y ago

True, although "the largest QR code" is substantially more dense than most people have ever encountered: https://en.m.wikipedia.org/wiki/File:Qr-code-ver-40.svg https://en.m.wikipedia.org/wiki/File:Qr-code-ver-40.svg . People might not realize that QR codes scale up and down very gracefully; most QR codes that people have ever seen probably encode less than 80 bits.

gregsadetsky 6y ago
Reminds me of a project a friend and I took part in, sending each other source code via postal mail. I ended up sending a QR code printed on film negative [0] to pack about 1k of bytes. Bellard's code is way more "information-dense" of course..! :-) [0] https://greg.technology/img/postal-codes.jpg https://greg.technology/img/postal-codes.jpg Edit: incredibly, pointing the iPhone camera app at the low-ish resolution photo of the QR code above works -- the QR code does decode. That's crazy.
- igravious 6y ago
  Hiya, how did you print these on negative film?
  - mirekrusin 6y ago
    You drill a hole in lead plate, take uranium rock, rasberry pi and...
  - gregsadetsky 6y ago
    In Montreal, the really really great people at Borealis [0] made it extremely easy. I sent them a 300 DPI file by email, and they printed negatives from those files in a few days. Each negative cost about $8 to print. Finding a lab that did this online was pretty difficult at the time. If others have recommendations -- please chime in! Otherwise, I would strongly recommend considering Borealis (who I'm sure can ship the negatives by mail -- otherwise reach out and I can facilitate the mailing as I live here ha) [0] http://www2.borealislab.qc.ca/borealis/en-home http://www2.borealislab.qc.ca/borealis/en-home
- orthoxerox 6y ago
  This reminded me of Richard Feynman and his first wife driving military censors bonkers by sending each other puzzles.
  - gregsadetsky 6y ago
    That's an incredibly kind comparison. Thank you! Do you have a reference where Feynman talks about this? I'm finding this [0]: "Arline entered the nearby Albuquerque sanatorium, from where she wrote him letters in code — for the sheer fun of it, because she knew how he cherished puzzles, but the correspondence alarmed the military censors at the laboratory’s Intelligence Office. Tasked with abating any breaches to the secrecy of the operation, they cautioned Feynman that coded messages were against the rules and demanded that his wife include a key in each letter to help them decipher it. This only amplified Arline’s sense of fun — she began cutting holes into her letters, covering passages with ink, and even mail-ordered a jigsaw puzzle kit with which to cut up the pages and completely confound the agents." [0] https://www.brainpickings.org/2017/10/17/richard-feynman-arline-letter/ https://www.brainpickings.org/2017/10/17/richard-feynman-arl...
    - 1986 6y ago
      He talks about it in more depth in Surely You're Joking, Mr Feynman, in the "Los Alamos From Below" section
- guerrilla 6y ago
  Why were you doing this?
  - gregsadetsky 6y ago
    It was an art project -- called "Postal Codes" -- where an artist friend and I would correspond by creating sketches (typically using p5.js or three.js) and sending them by "snail" mail. There is a bit more information here [0], here [1] and here [2]. [0] https://www.instagram.com/p/B9MhMzKHVxJ/ https://www.instagram.com/p/B9MhMzKHVxJ/ [1] https://www.instagram.com/p/B7wL7MKly3k/ https://www.instagram.com/p/B7wL7MKly3k/ (description in Spanish and then English) [2] https://github.com/gregsadetsky/postal-codes https://github.com/gregsadetsky/postal-codes (project description, "rules", and source code)