sgt-puzzles/html/mosaic.html

Mosaic
<p>
Colour every square either black or white.
Each number indicates how many black squares are in the 3&times;3 square
surrounding the number &#8211; <em>including</em> the clue square
itself.
<p>
Left-click in an empty square to turn it black, or right-click to turn
it white. Click again in an already-filled square to cycle it between
black and white and empty. You can left- or right-drag to set multiple
squares at once.