Connect Four is a two-player game with perfect information for both sides, meaning that nothing is hidden from anyone. Connect Four also belongs to the classification of an adversarial, zero-sum game, since a player's advantage is an opponent's disadvantage.

One measure of complexity of the Connect Four game is the number of possible games board positions. For classic Connect Four played on a 7-column-wide, 6-row-high grid, there are 4,531,985,219,092 positions for all game boards populated with 0 to 42 pieces.

To play the game click on any row/column and the corresponding empty circle(low level) will be occupied with either red/yellow color (first red and than yellow) .

For more information : https://en.wikipedia.org/wiki/Connect_Four