I adore regex crosswords. I believe the first one I'd ever seen was from the MIT Puzzle Hunt (http://www.coinheist.com/rubik/a_regular_crossword/grid.pdf), although it wouldn't surprise me if they'd existed earlier.

However, I find this site a bit frustrating. I love the idea, I love that they have so many puzzles, and I love the UI they've built. But I don't want themed puzzles that I can solve without having to crunch the regex themselves – if I was interested in that, I'd do a regular crossword.

I'm pretty sure "A Regular Crossword" was the first one to come to the public's attention. When solvers came across it during the 2013 Hunt, we were very surprised and impressed and enthusiastically told our friends about it.

It looks like a squatter has gotten ahold of coinheist.com; a correct permanent link is

http://www.mit.edu/~puzzle/2013/coinheist.com/rubik/a_regula...

The solution (with author credits) is at

http://www.mit.edu/~puzzle/2013/coinheist.com/rubik/a_regula...

Excellent! I only wish the column clues were tilted so that I could read them without having to crane my neck.

Yes, as it is now it's unreadable, I came here to make the same point. Tilted to the right starting above their column would make the most sense. I can barely read text in it's current orientation let alone regex's.

On either side of the "validate" button at the bottom are controls to rotate the puzzle to this end.

That's still not acceptable, now it's harder to read both.

Considering that (from their stats page), 15k people have answered 326k puzzles, I'm pretty sure it's "acceptable" to somebody.

Those buttons could do with a 'position: relative; z-index: 1' so they are still easy to click when the table is rotated and overlaps them.

Edit: Coworker pointed out you can rotate the board to read it better.

Holy crap, that's 1000x better.

Second comment, probably deserving its own discussion: if you're familiar with Shakespeare (or Google) once you solve about half the puzzle, the full answer is trivial to guess Wheel-of-Fortune style - and kind of robs you of having to puzzle out the rest of the regular expressions.