Nurikabe
Rules
1. Fill in the cells under following rules.
2. You cannot fill in cells containing numbers.
3. A number tells the number of continuous white cells. Each area of white cells
contains only one number in it and they are separated by black cells.
4. The black cells are linked to be a continuous wall.
5. Black cells cannot be linked to be 2x2 square or larger.
Features
Nurikabe rules are more complex than some other puzzles, but it is still popular with both beginners and experts.Black cells stretch like mollusc and make a linked wall on the grid. As the cells stretch and be linked, you will feel the sense of achievement. The starting point is 1 (you can fill four cells of its sides; up, down, right, and left cells). Enjoy!