When someone sends me a link, claiming they’ve uncovered the most difficult crossword they’ve ever seen, I’m usually skeptical.

I mean, I’ve seen some diabolical crosswords in my day. From puzzle 5 at the American Crossword Puzzle Tournament and the meta-puzzles lurking in Matt Gaffney‘s Weekly Crossword Contests to the Diagramless and Double Trouble crosswords offered by our friends at Penny Dell Puzzles, it’s hardly tough to find challenging crosswords these days.

But this puzzle, originally created for the 2013 MIT Mystery Puzzle Hunt and made solvable (and rotatable!) online by Greg Grothaus, might just take the cake:

As you can see, there are clues across three sides of the hexagonal grid: the across clues, the down-to-the-left clues, and the up-to-the-left clues.

But these clues are unlike anything I’ve seen before.

It turns out that these are regexps, or regular expressions, sequences of characters and symbols that represent search commands in computer science.

Now, anyone who has used graphing features in Excel or crossword-solving aids on websites like XWordInfo, Crossword Tracker, or OneLook is probably familiar with simple versions of regexp. For instance, if you search C?S?B?, you’ll probably end up with CASABA as the likely top answer.

Of course, the ones in this puzzle are far more complicated, but the overlapping clues in three directions make this something of a logic puzzle as well, since you’ll be able to disregard certain answers because they won’t fit the other clues (as you do in crosswords with the across and down crossings in the grid).

But if, like me, you don’t know much about reading regexp, well then, you’ve got yourself a grid full of Naticks.

If anyone out there is savvy with regexp, let me know how taxing this puzzle is. Because, for me right now, it’s like doing a crossword in a foreign language.

But I’m not the only one who feels this way. When I first checked out the post on Gizmodo, they titled it “Can You Solve This Beautifully Nerdy Crossword Puzzle?” and I laughed out loud when the very first comment simply read “Nope.”

Glad to see I’m not alone here.

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