In case anyone else is interested: https://en.wikipedia.org/wiki/Rectangular_Micro_QR_Code
I think it's this: https://www.qrcode.com/en/codes/microqr.html
About 5 minutes later there was another tweet from him where:
- someone saw the original tweet (Guy 2)
- scanned the QR code
- ordered the OP a drink
- added a note to the order saying it was from Guy 2
Always loved this story.
QR Code® is [sic] registered trademark of DENSO WAVE INCORPORATED.
I used something like this on a large sheet and cut it into pieces for a puzzle gift to a website where people left comments. Nowadays even easier to generate nice temporary websites for such things.
The starter kit: a 21×21 board, with three 8×8 finder patterns, two 1×5 timing patterns, and 120 white and 119 black modules.
The Version 2 expansion pack includes a 25×25 board, two 1×4 timing patterns, one 5×5 alignment pattern, 76 white modules and 75 black modules.
And so on.
(I dunno about the desired ratio of individual black and white modules. I gather the general idea is to balance black and white, but does that include or exclude the fixed parts, where black is somewhat more common? Finder pattern is 33∶31 black∶white, alignment pattern is 17∶8, 1×5 timing pattern is 3∶2, 1×4 timing pattern is 2∶2.)
This is a nice trick worth remembering. I have used it myself in the past. Handy not just for creating ultra small QR codes, but also for getting as much data as possible into the limits of the largest QR codes.
It's cool for the receiver, but tedious for the sender (but it's a good way to help with difficult to read cursive).
Well... it wasn't QR-code but rather artoolkit markers. Let's just say I'll keep on printing them for a bit.
Maybe I can try again with the help of LLMs. Hmm not a bad idea
https://typefully.com/DanHollick/qr-codes-T7tLlNi
Here's a HN discussion from 2022 about it.
https://www.nayuki.io/page/creating-a-qr-code-step-by-step
This is an interactive guide that will break down the process for your specific QR-code.
