(Click on the image to begin the animation)
The Celtics have a problem with zones. That's nothing new. Their problem with zone defenses begins with their desire to spot up from 3. The C's love the 3... and it kills them because they'd rather stand behind the arc than attack gaps.
This diagram is pretty much what the Clippers were playing at points in the 2nd quarter. The double team on the low block came on Glen Davis. .
Guys are taught to look "high-opposite"... meaning if you're in trouble on the block, the guy who is high on the opposite side of the court is your first look to get out of trouble. The high-opposite guy is Eddie House. During the game, Eddie stood outside the 3 point line and waved his arm frantically.
Davis spun, tried to make the very long pass... and it got stolen by Mardy Collins who went in for the dunk.
In the animation, you'll see what Eddie should have done.. which is attack that area in between the defenders. Everyone was looking at the ball... a natural tendency... which left a dive into the lane wide open. Had Eddie done that, the natural "Oh crap" reaction from the defenders would have caused them to collapse on him.
That suddenly leaves 3 wide open options... one on either wing, and one up top. The guy on the right was Tony Allen... who could have taken a little bounce pass from Eddie, attacked yet another gap and maybe get to the rim. Rasheed Wallace was to the left for a nice 12-15 foot jumper. Glen Davis could have sealed and maybe gotten a pass in the middle somewhere. And the worst case scenario was Bill Walker behind him to reset the play.
You attack a zone defense because guys are covering areas. Certain areas overlap, which means two, or more, guys will react to one guy's penetration because that player is attacking an area of shared responsibility. When you continue to attack these areas, you pull guys out of position and create wide open spots on the floor. Do it enough and you'll get into the middle of the zone and you could have all 5 guys reacting to you... then you pick your target.
The bottom line is... standing around makes the zone effective. It allows guys to cover a lot of space and make plays in passing lanes. If you want to beat the zone, you attack it hard and break it down... which the Celtics haven't been doing.