Britain’s top spy agency has just sent out its Christmas card and, as you’d expect, it comes with an catch. Don’t worry though, it’s not timed to self destruct.
The card doesn’t have a nice picture of a snowy village or a shitty Christmas joke, instead the spies have hidden their Christmas message in a secret code.
Clever participants have to solve a puzzle to reveal an image.
To solve the puzzle you have to know that each square is either black or white. Each row or column is labelled with a string of numbers which tell you the length of consecutive runs of black squares, and are displayed in the order that the runs appear in that line.
The GCHQ website gives the example that a label “2 1 6” indicates sets of two, one and six black squares, each of which will have at least one white square separating them.
As it’s Christmas, the spies have lent a hand, some of the squares are already coloured to make it a bit easier. Apparently if you can solve the puzzle it then leads to a series of more complex challenges.
GCHQ director Robert Hannigan sent the puzzle out to his Christmas card list. If participants can solve all the puzzles then they can email their answer to GCHQ by January 31.
If you fancy the challenge but aren’t on the spies mailing list you can have a go here. Those who enjoyed the brainteaser have been asked to make a donation to the National Society for the Prevention of Cruelty to Children.