[readerrrr]

edit: I'm wrong.

I have found a correct solution, yet the game doesn't accept it:

B r r B

r B B r

B B r B

B r B r

The correct solution was:

B r r B

r B B r

B B r r

r r B B

My guess to this is that there are more than one solutions to the problem and checking if the board is solved is done by finding the first solution and comparing it to yours.

[function_seven]

Your third row contains 3 B's and only one r. Each row and column has to have an equal number of each.

[readerrrr]

Well that's embarrassing.

[function_seven]

Earlier today when I saw this thread I came to post my game that "should have won but didn't", only to see to many other people posting the same. For me it was the "no duplicate columns or rows" rule that I didn't notice. Something about this game is tripping a lot of people up.

[readerrrr]

The thing is I know about the rule of equal number in each row and column, and have used it to solve a few 10x10, but when switching to a 4x4 I forgot it exists. I took some time and went trough the rules I knew, before posting this "error", but that one rule was gone.