Poole graphic designer James Addison writes puzzles for postmen. Instead of addresses on letters he creates elaborate codes, pictures and puzzles in a bid to outsmart the Royal Mail's detectives.
The project started as a challenge for Frank, the postman in James' home village in Buckinghamshire, but has spread.
Despite the wide range of puzzles, including some that simply have a picture of the building to deliver the letter too, none of the cryptically addressed missives have ever gone astray.
We'll be talking more to James about his project next week, but for now, watch him explain it in his own words.