# Test Your Smarts With the British Spy Agency’s Christmas Card Puzzle

## Can you solve this head-scratcher?

smithsonian.com

Need a break from spending time with the family this holiday season? The United Kingdom’s Government Communications Headquarters (GCHQ) has a puzzle for you. This year, the British spy agency is sending its employees a wickedly complicated grid-shading puzzle inside its traditional holiday card.

The puzzle looks kind of like a crossword, only instead of figuring out which letter goes in each box the player has to figure out which boxes to shade based on long strings of numbers. As the GCHQ website explains:

In this type of grid-shading puzzle, each square is either black or white. Some of the black squares have already been filled in for you.

Each row or column is labeled with a string of numbers. The numbers indicate the length of all consecutive runs of black squares, and are displayed in the order that the runs appear in that line. For example, 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.

But the puzzle is only the first step. According to GCHQ, filling in all the right boxes will create an image that will lead the player to the next puzzle in a series.

Once they finish all of the puzzles, the player will be invited to submit their answers to GCHQ via email, and the agency will choose a winner out of the final pool of puzzlers. In their statement, GCHQ also requests that players make a donation to the National Society for the Prevention of Cruelty to Children in the spirit of the season.

If you want to stand a chance of getting your answers in early, though, you may want to hustle. It’s been barely a day since GCHQ posted the puzzle and communities of puzzle-solvers are already popping up on internet forums like Reddit, Esther Addley and Fred Searle report for The Guardian.

GCHQ’s director, Robert Hannigan, may have hoped that the puzzle would “exercise the grey matter over the holiday period,” according to the agency’s statement, but as of Thursday several players claimed to have already moved on to the fifth and possibly final puzzle.

The puzzle’s popularity seems to have caught GCHQ a bit by surprise, as a spokesman told Addley and Searle that their website shut down from the flood of people rushing to download the puzzle. Despite the number of people who have already made it through all five puzzles, the spokesman said the agency has yet to receive any correct answers.

As for the prize? Don’t expect to be awarded 00 status or be asked on a top-secret spy mission. The winner will probably just get “something small, not a trip around the world,” the spokesman told Addley and Searle. “It’s just for fun.”