Nurikabe ©
Rules
You have to find white islands surrounded by a black wall. Each given number in the grid belongs exactly to one white island. The given number defines the number of white adjacent cells belonging to that island. All black cells are linked to be a continuous wall. Black cells cannot be linked to be 2x2 square or squares or larger. Mark in black all the cells belonging to the wall!
Sample puzzles
EASY
MEDIUM
HARD
EVIL
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