4 in a Line or Four in a Row is a two-player connection game in which the players first choose a color and then take turns dropping colored discs from the top into a seven-column, six-row vertically grid. The pieces fall down, occupying the next available space within the column. The objective of the game is to be the first to form a horizontal, vertical, or diagonal line of four discs. There are many options: - Play against computer AI or against a local human partner; - Four difficulty levels