limits of its number), an island can only expand into one cell, then that
-#. If an Island reaches certain points
that reaching them consume s all of its
+#. If an Island reaches certain points consume all of its
number, then its white edge points can be marked with black in the opposite
We can see that the island should expand into the leftmost gray/unknown cell
or else it will need to take a costly detour which will consume the rest of its
+#. Islands that can expand in several different manners must mark all the
+common black cells inflected by these ways in this way. For example:
+The lower-right [G] cell must be black because it will be black whether the
+2 expands to the right or to the bottom.
+In addition, if we have:
+The the 4-cell region can only expand into (x2,y3) or (x3,y4) so
+[G](x2,y4) must be black.