Testing the Postal Service

I found this story brilliant:

http://www.independent.co.uk/arts-entertainment/art-and-architecture/news/return-to-sender-artist-puts-royal-mail-to-the-test-955499.html

Illustrator Harriet Russell put the postpersons to the test by concocting puzzles hich resolved to addresses. From 130 letters sent, 120 arrived. The example puzzles are pretty good, I failed the colour blindness one :-(