1 Line is a brain-training puzzle in which you draw 1 line, that will sharpen your wits. In this free-to-play puzzle game, you merely have to draw one line. It is deceptively simple, yet profoundly deep. Play through the extensive stages, sharpening your wits as you have fun. How to play: There is only one rule: “Connect all the points with just one line.” It doesn’t matter where you start.