Solve a Nurikabe puzzle by shading the sea around its islands.
Nurikabe, also called Islands in the Stream, asks you to shade some cells
black to make a sea. Each numbered cell belongs to a white island of exactly
that many cells, islands never touch each other orthogonally, all of the black
sea is connected, and the sea never contains a 2 by 2 block. Type a number
into each clue cell, leaving the rest blank, then solve.
Enter an island size, or leave a cell blank.
Solution
How it works
The solver places one island at a time, trying every connected shape of
the clue's size that contains its number and never touches another island.
Whatever cells are left over become the sea, which it then checks for a
single connected region with no 2 by 2 block.
A proper Nurikabe has one solution; the solver reports when more than one
shading fits.