[AlexSolution]

I found http://regexcrossword.com/ to be a good learning tool.

Here's one if you really want to test your skills: http://i.imgur.com/qLh2gcK.jpg

[pajop]

SPOILER ALERT: answer to regex crossword referenced by the 2nd link: http://www.mit.edu/~puzzle/2013/coinheist.com/rubik/a_regula...

[markild]

Really like this idea!

Off topic, but, I don't see why people don't make alternatives to this

> Notice! In order to save your progress you have to login with Facebook.

Let me save by cookie as well, please.

[leeoniya]

i'm not sure if this puzzle is meant to be a joke, but it pretty much looks like it.

things like (O|RM|HHM)* which means match anything. who the hell would every write (.)(.)(.) when even capturing those is pointless in a crossword.

meh, i say.

[markild]

I'm not entirely sure what you are saying, but I actually find this puzzle quite interesting.

(O|RM|HHM)* doesn't match "anything", but rather "nothing" or something quite specific. [0]

There are multiple rows in the puzzle where things _can_ match anything, but they are pretty fast limited by the opposing row/column.

[0]: http://www.regexper.com/#%28O|RM|HHM%29*

[leeoniya]

yeah sorry, wrote that in a hurry. i meant, if it can match nothing and still be valid, what's the point? you may as well write `.*`

[TophWells]

Well, remember that it also has to fit in the row/column. If there's three spaces available, the string has to have three characters. So (O|RM|HHM)* can only really match ORM, RMO, and HHM.

[oneeyedpigeon]

And OOO.

[TophWells]

Forgot about that one.