Ten days ago we posted a cryptogram puzzle, set by mathematician and author Josh Holden. We’ve had a number of entries, some which were so enthusiastic they ignored that we’d said to email them in and tried to post in the comments. However, from the correctly submitted entries, we had one stand-out winner – a quick reply, with a detailed description of the solution and a worthy recipient of a copy of The Mathematics of Secrets. Here’s Josh’s explanation of the puzzle, for anyone who hasn’t cracked it yet.