The point man starts the offense by passing to the wing.  At that point the middle man (#4) steps out to the perimeter as #1 is fading to the opposite wing.  The opposite wing (#3) is flashing into the free throw lane area looking for the pass from #2.

Notice that you will have an easy reversal unless the other guard steps out to play that pass.  Since this action is happening right in front of the guard they almost always follow the middle man out opening up the middle of the zone to attack.

That allows us to hit #3 in the middle, forcing the Center of the zone to step up and guard us.  
We usually get a few open shots before the big man will come out and pick us up.  Then we can simply drop the ball to #5 who is sealing out the forward for an easy score.

If we don't get the middle man we reverse and repeat the pattern.  
The problem for the defense is covering the other wing now with a forward.  The center (#5) is coming across the lane and draws the center of the zones attention.  #2 is flashing into the middle of the zone and is wide open.

#3 has created the middle opening by stepping out to the top of the key.

In this example we hit #2 in the lane which many times forces the backside wing to guard him or at least step that way and turn his head away from #4 cutting to the hoop.  

We get a lot of easy lay-ups against a zone defense that is supposed to be forcing us to shot from the outside.