It needs a new kind of punch that can't easily be photographed and it needs to be waterproof. Magnets seem good. Could make them disc shaped.... wait...

Please see my reply to this other similar question:

> Looks like a new 2d barcode format to me. Why I would want this rather QR or any other that have redundancy built in?

https://news.ycombinator.com/item?id=44145202#44145279

This will survive a house fire.