NURIKABE

In these puzzles, your goal is to create isolated white areas surrounded by black walls, such that each white area has only one number and the number of cells in a white area is equal to the number in it.
A few other rules must be kept in mind as you solve: Cells containing numbers cannot be blackened, and the cells that are blackened must be linked into a continuous wall, as in the example at right. Also, you cannot form a block of black cells 2×2 or larger. Best place to start? Pick a 1, and draw in black squares on all four of its sides.

HINT