1. Buy an apartment next to a well lit outgoing post box. 2. Install a system of mirrors to peek at the letters being inserted into the box 3. Reuse one code

1. Buy an apartment next to a well lit outgoing post box. 2. Install a system of mirrors to peek at the letters being inserted into the box 3. Reuse one code for a 50% chance of saving 1 euro and delivering your mail for free. 4. Send each letter 7 times, each with a different duplicate code, for a 99% chance of at least one free delivery. Not worth the effort and I’m sure this would be tracked and stopped immediately. But it’s cool that in theory this seems possible.