Square-Off is a puzzle game, based on the Japanese nonogram puzzles (Sometimes called Griddlers, or paint by numbers). Your object in the game is to uncover all the black squares in the grid. To help you solve the puzzle, the number of black squares in each row and column is displayed. The game can be difficult at first, but the techniques are easy to learn. There are 3 skill levels - at each level the board gets bigger, and the game much more hard to solve.
Very similar to the popular Sudoku game, Square-Off is an excellent form of exercise for the brain.