10 seconds of audio encoded on to paper.
It's analog, not digital, so it survives abuse a lot better.
There's a blank sheet available there, so you can sketch one out by hand.
The technology being used is based upon the Russian ANS, and the same developer has a Virtual ANS:
The default may be small, but with the Virtual ANS, I can make it song length.
... and I have a touch screen, so this will be fun.