It's a two player game or you can also play against Computer.
It's also known as Paddocks, Pigs in a Pen, Square-it, Dots and Dashes, Dit Dot Dash, Dots, Line Game, Smart Dots, Dot to Dot, Dot Boxing, Dot Game.
Starting with an empty grid of dots, players take turns adding a single horizontal or vertical line between two unjoined adjacent dots. The player who completes the fourth side of a 1×1 box earns one point and takes another turn. (Initial of the player is placed inside the completed box). The game ends when no more lines can be placed. The winner is the player with the most points.