We will now look at the '3 1' clue on the right of this puzzle. The neighbours of this
cell are A, B, C, D and E. There are 2 possible combinations for how this clue can be
- B B B W B
- B W B B B
You will notice that some cells are Black for both of these combinations, i.e. cells A, C,
and E. We can set these to Black.
There is a similar '3 1' clue at the top of this puzzle that we can apply the same reasoning to.
Also note that there is a '3 1' clue at the bottom of this puzzle with only one way these
clues can be satisfied.