Please read...stop whining about NT perception....
Unlike the vast majority of NFL teams who run a variation of the same scheme week in and week out, the Patriots are game plan specific. This means that their entire defensive approach changes from week to week depending on the strengths, weaknesses and tendencies of the opponent. Very seldom do you see the Patriots run the same scheme two consecutive weeks or even against the same opponent a second time.
For example, one week they might blitz a lot with pressman coverage. The next week, they will play zone and force the mobile QB to try and beat them from the pocket. Another week, they'll switch from the 4-3 to a 3-4 defensive front in an attempt to disguise where the blitz is coming from.
2. Take away what the opponent does best.
The Patriots' approach is to neutralize the opponent's biggest threat and make them try to beat you left handed. Whether that means devoting two players to stop an opposing WR or having your DEs and OLBs hit the TE or RB every time he releases, the Patriots defensive scheme is built around the idea of disrupting the offense's natural tendencies and timing and forcing the offense to adjust - something that many offenses seem to struggle with.
3. The Patriots prefer their defensive linemen to two gap.
Most NFL defensive lines utilize the one-gap technique. That means each D-lineman is responsible for a gap between two O-linemen and his job is to get in and through that gap and cause havoc in the backfield. The Patriots usually prefer their D-linemen to read and react to the play by controlling the O-lineman in front of them and being responsible for the gap on either side of him. The benefit of this approach is that you keep the play in front of you and you usually free up the LBs to clean up the play by preventing the OLs from getting their hands on the LBs. This isn't to say the Patriots never have their DL one gap, but that the more common technique they use is two-gapping.