[help] O-P-6X6-14-8242

[casimodo]

https://imgur.com/a/89hlHyp

Any mine-master around? I don't see it. I can come up with a solution with both options in the green hint (mine or non-mine). If it's a mine, the place two squares below should be free.

[Perseus]

If it's a mine, how would the mines down-right of it ever connect to the outside?

[Quote]

There's a nice theorem with Outside. Picture a 2x2 "checkerboard" of mines and safe squares. The safe squares have to connect to each other, and the mines have to connect to the border. What can you say about the possibility of such a pattern in a puzzle with the Outside rule?

[casimodo]

Ah, the Socratic way, I see :) Thanks for the message
Hmm.. I can say that the only invalid pattern is the diagonal one: if there are two non-mines, they should touch. if there's 1 or 3, it doesn't matter.

(some paint-planning after...) Oh, apparently it can not be a mine.. otherwise either the mines are isolated, or the non-mines are unconnected.

PS: this is largely the most difficult puzzle I have encountered so far in the game. I wonder if different people have trouble with different variants

[Quote]

Originally posted by casimodo:

Oh, apparently it can not be a mine.. otherwise either the mines are isolated, or the non-mines are unconnected.

Yes, so such a 2x2 checkerboard can never appear anywhere in an Outside puzzle. The hinted square must be safe to avoid a checkerboard pattern.

[casimodo]

I had it in front of my nose..! thank you again for the clarification, Quote!
Quite a silly thing for me to miss..