O or X is very classic puzzle game that everyone used to play in early childhood since long ages. The game is also known as 'Tic Tac Toe' and 'X and O'. Whatever it is named or called, the playing rules are pretty similar! You need to match 3x3 OR 5X5 blank spaces by putting your mark either X or O. You can play alone against the device itself or you can choose two players to play. All you need to match successive rows either horizontal, diagonal or vertical pattern. You have to be smart to win and choose blocks wisely You will have options to note your winning times, if you play with two players option.