Tic-tac-toe

Theplayer(X)playsagainsttheAndroidApp(O).Thetwoplayersplacetheirmarkalternatelyona3x3squareswideplayingfield.Whosetsthefirstthreeofhischaractersinarow,columnormaindiagonalisthewinner.
Skilllevelofyouropponentcanbeadjusted.
Idea/theory:https://en.wikipedia.org/wiki/Tic-tac-toe