The object is to create islands by partitioning between clues with walls so that the number of squares in each island is equal to the value of the clue, all walls form a continuous path and there are no wall areas of 2x2 or larger. Each island must contain one clue and be isolated from other islands horizontally and vertically.
There is only one unique solution for each puzzle.
First click fills the square to indicate it is part of the wall, second click marks a dot to indicate the square is part of an island and third click brings the square back to its original state. Multiple squares may be filled or dotted by dragging the mouse.