From the update: &quot;Why are QR Codes with capital letters smaller than QR codes with lower-case letters?&quot; <a href="https:&#x2F;&#x2F;shkspr.mobi&#x2F;blog&#x2F;2025&#x2F;02&#x2F;why-are-qr-codes-with-capital-letters-smaller-than-qr-codes-with-lower-case-letters&#x2F;" rel="nofollow">https:&#x2F;&#x2F;shkspr.mobi&#x2F;blog&#x2F;2025&#x2F;02&#x2F;why-are-qr-codes-with-capit...</a> (<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=43149077">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=43149077</a>)

If someone needs a gift idea: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.

By the way, I also coded a QR symbol generator in PDP-10 assembly language.<a href="https:&#x2F;&#x2F;github.com&#x2F;PDP-10&#x2F;its&#x2F;blob&#x2F;master&#x2F;src&#x2F;lars&#x2F;qrcode.8" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;PDP-10&#x2F;its&#x2F;blob&#x2F;master&#x2F;src&#x2F;lars&#x2F;qrcode.8</a>

I hand drew this on a whiteboard. It was a lot more work than I anticipated.<a href="http:&#x2F;&#x2F;lars.nocrew.org&#x2F;tmp&#x2F;qr.png" rel="nofollow">http:&#x2F;&#x2F;lars.nocrew.org&#x2F;tmp&#x2F;qr.png</a>

I found this page very helpful in understanding each step of the QR code creation process. I can&#x27;t say I recall it all but it would be possible to turn this into a small booklet, I guess.<a href="https:&#x2F;&#x2F;typefully.com&#x2F;DanHollick&#x2F;qr-codes-T7tLlNi" rel="nofollow">https:&#x2F;&#x2F;typefully.com&#x2F;DanHollick&#x2F;qr-codes-T7tLlNi</a>Here&#x27;s a HN discussion from 2022 about it.<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=32837565">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=32837565</a>

One time I tried to understand the QR algorithm and I didn&#x27;t understand it at all despite trying multiple times.Maybe I can try again with the help of LLMs. Hmm not a bad idea