Stumbled onto http://picme.heroku.com/ via a tweet by @SteveStreza. Top post was a photo of a QR code. I tried to scan it but it wouldn’t register because it was a mirror image.
ACHIEVEMENT UNLOCKED
Learned something new.
It’s kinda obvious, but I had never come across this before. QR codes don’t work mirrored.
They do work upside down or sideways, though!