ref: f1756279d2847aaac33fc3db767cbd23aa69c229
dir: /html/lightup.html/
Light Up <p> Place light bulbs in the grid so as to light up all the blank squares. A light illuminates its own square and all the squares in the same row or column unless blocked by walls (black squares). Lights may not illuminate each other. Each numbered square must be orthogonally adjacent to exactly the given number of lights. <p> Click on a square to place or remove a light. Right-click to place a dot indicating that you think there is no light in that square.