3D Balls in Line can be played by two persons. The players have to place pieces into the game ducts, one by one, trying to obtain a horizontal, vertical or diagonal line of the same color. The objective of the game is to make the most such lines.

Rules for "3 balls in line"
The players have to place the pieces, one by one, in any of the ducts (holes), trying to obtain a lines of three pieces horizontal, vertical, or diagonal of the same color. The winner will be the player who make the most complete lines.

As a particularity of this 3x3 logic game, the player who placed the central piece, which can became hidden during the game, must claim that by saying "central". The rest of the pieces are completely visible during the game.

Rules for "4 (or more) balls in line"
The players have to place the pieces, one by one, in any of the ducts (holes), trying to obtain lines of four pieces, horizontal, vertical, or diagonal, of the same color. The winner will be the player who makes the most such lines.