My suggestion:
If two (diagonally or orthogonally) neighboring cells within the same box contain consecutive numbers the cell with the higher number is shaded. All possible shaded cells are given.
I am not completely sure about my proposal but I post it for discussion purposes. I think that Dandelo's suggestion misses the "in the same box" constraint.
If two (diagonally or orthogonally) neighboring cells within the same box contain consecutive numbers the cell with the higher number is shaded. All possible shaded cells are given.
I am not completely sure about my proposal but I post it for discussion purposes. I think that Dandelo's suggestion misses the "in the same box" constraint.