In Cryptic Crosswords Club, we tackle this devious type of word puzzle that is a delight for mathematical brains.

Each clue of a cryptic crossword is a word puzzle, and requires the solver to unravel a tricky bit of wordplay to find the answer. For example, in the clue "Arrived before large humped animal" for the word CAMEL, the 'large humped animal' part provides the definition while 'arrived' clues 'CAME' and large is abbreviated as 'L'. This type of clue is called a charade.

I first ran cryptic crosswords as a Flex Friday activity last year. When I was an undergrad at the University of Chicago math department, some of the graduate students and a professor did a British cryptic crossword at tea every day. By watching and later joining in, I slowly learned how to do these British cryptics (no easy feat—they use British terms like 'test' for a cricket match and 'Bridlington' for British resort town.) Solving a cryptic clue rewards you with the same 'aha' moment that solving a good math problem does, and the same certainty that you are correct, so I thought that Proof School students might enjoy this puzzle type. There was only one problem: there are no published cryptics that are aimed at beginners.

So, I set out to write my own puzzles for the kids, in collaboration with a friend. This has been a lot of fun, because we can include secret messages for the Proof School kids in the grid, or theme answers based on recent events (like National Bean Day, or, last year, the obsession with the game the Resistance led to a grid that had hidden spies.) On inauguration day, we had a cryptic with presidents: it featured, for example, the clue "Misplaced my nickel in the place now (and formerly!) known as Denali (8)". The answer is MCKINLEY, a place now and formerly known as Denali. As for the wordplay: 'misplaced' indicates that you should anagram the letters in `my nickel'. I am very excited for Monday's upcoming cryptic: we designed a new mechanic for revealing the secret message which is more complex than students have seen before.

Along the way, the students have also had a chance to try their hand at creating cryptics. Last week, I set a grid with a hidden message, and they got to work writing clues. I was impressed at the quality of their clue writing. We will format their puzzle and distribute it to anyone who is interested!

It has been a joy having the opportunity to run cryptic club this year and last year and to introduce a new type of puzzle to students at Proof. If you're interested in trying your hand at a cryptic, here's the Wall Street Journal's Guide to Cryptics and the first cryptic we tackled this year. Hint: there is a secret message hidden if you read around the edge—note the date of the puzzle.

-- Sachi Hashimoto