“This is an example of a defensive foul where the defender’s arms extend over the offensive player’s vertical space. The post defender, Jayson Tatum, does have his body in a vertical position, but his arms are tilted forward over the vertical space of his opponent, Al Horford. Even though contact is then initiated by the offensive player’s upward shooting motion, the foul is called on the defensive player for being in an illegal position at the time of the contact. This is a defensive foul, and it occurred with the offensive player in the act of shooting. Post defenders must maintain a vertical position in order to be considered legal when the contact occurs.”