diagonals :: Board -> [[Cell]] 
diagonals b = [[b!!0, b!!4, b!!8],
               [b!!2, b!!4, b!!6]]
diagonals :: Board -> [[Cell]]
diagonals b = [[b!!0, b!!4, b!!8],
               [b!!2, b!!4, b!!6]]
diagonals b = [[b!!0, b!!4, b!!8],
               [b!!2, b!!4, b!!6]]