Example puzzle
This is an example puzzle. You can solve it the same way as you would solve competition puzzle, but result never stored. You can reveal an answer for the puzzle by clicking "Show answer" link.
Kuromasu
Author: Andrey Bogdanov
Blacken some cells in the grid so that no two black cells have a common edge and all white cells are connected. Cells with a clue cannot be blackened. Clues indicate the total count of white cells connected vertically and horizontally to the numbered cell including the cell itself.
Grid control: Click the mouse button at the selected cell to change the color of the cell. Second click will put auxiliary cross sign, which doesn't affect correctness of the solution, but helps visually. You can also drag the content of one cell to another with the mouse. More details about grid control are at the help page.