* players begin in position as shown in the diagram - one point guard, two wings, one high post, one low post - essentially the same layout as the 1-3-1 zone, except extended past the half
* the point guard (#1) needs to angle the ball carrier, forcing him to one side
* the two wings remain behind the half court line, allowing enough room between them and the half court line so that the ball carrier doesn't realize right away that a trap is coming
* the weak side wing (#3 in the diagram), once he realizes he is the weak side, can drift closer to the half court line if there is another offensive guard there - anticipating the possibility of a lateral pass from the point guard
# the wing on the ball side (#2) must wait for the ball carrier to cross half - if he jumps to quick, the ball carrier can still reverse his dribble and move across the court. But if the wing (#2) waits for the ball carrier to cross half, then the ball carrier is effectively trapped by the defense as well as the half court line and the sideline - in other words, a four man trap!
# the moment the ball carrier crosses half, #1 and #2 trap him in the corner.
* the defensive players not on the trap must now move aggressively to steal any pass that the ball carrier tries to make
* to do this, they must position themselves in the path of any offensive player that may get passed to