Pigs-and-Sties (a.k.a. Dots-and-Boxes ) is a two player games.
The player take turns to draw vertical or horizontal green lines by tapping on the grey lines.
if a player completes a box his sign (X or O) is placed in the box and another line has to be drawn,
The turn continues until a line is placed that doesn't complete a box. Who finishes the most boxes wins.