井字棋 is a classic paper-and-pencil game, also known as Tic Tac Toe.

FEATURES: - lots of game modes (the classic 3x3. the 3D version 3x3x3 and other variants) - 3 difficulties (easy, medium and hard) - single player, two players on the same device, two players online - google play games achievements - google play games leaderboards - online multiplayer

RULES: - the board can be 3x3, 3x3x3, 5x5 or 7x7 - two players play alternatively, marking one empty cell at a time - the objective (equal to 3, 4 or 5) is the number of markings to achieve in line (horizontally or vertically or diagonally) - the 3x3x3 should be visualized as a cube (check the screenshots for some winning possibilities)

Stop wasting paper and save some trees! =)