I did a hexagon problem like this earlier . . . it helped me to make the matrix 12x6 as well, but when checking fromt op to bottom sometimes you have to say:

check(r+2, c);
check(r+1, c+1);
check(r+1, c-1);

and I can't remember, but I also thing I ended up trying:

check(r-1, c-1); and check(r-1, c+1); as well . . ., making sure it didn't go backwards to the spot it just came from, but I'm not sure about those.

That got somewhat confusing at times, but it worked for me. Good luck man, those hexagon problems are a beast...lol.