Each row and column contains the same number of O and X. The same symbol never appears in three adjacent cells, horizontally or vertically (e.g. ?XX? must be OXXO). Also, each row and each column is unique.
MORE SYNDICATED CONTENT
Sudoku Puzzles.
Each row and column contains the same number of O and X. The same symbol never appears in three adjacent cells, horizontally or vertically (e.g. ?XX? must be OXXO). Also, each row and each column is unique.
MORE SYNDICATED CONTENT