PHOENIX -- It is as difficult to pin a tag on the New England Patriots as it is to defeat them.
New England is trying to become the third team to win four Super Bowls in a single decade and, like the two teams that already did it, the Patriots have reached this point because they are so good at re-inventing themselves.
They can change styles not only from game to game but from series to series within a game. They can play a 4-3 on defense or a 3-4 or even something more exotic. They can run a shotgun offense with five wide receivers or a close formation with three tight ends. They can do any of these things equally well, and they will do them as often and as long as they have to without giving it a second thought.
"If you're playing the Patriots in the 10th game of the season, you'd better study what they did not only in the ninth game, but all nine games -- and preseason, too," said Randy Cross, who started on the offensive line for three San Francisco Super Bowl winners in the '80s and now is a TV analyst.
That, of course, is how a team can stay ahead of its competition.
There is also a bit of show-off in how the Patriots play. Tell them something can't be done, either because of past performance or strategy, and they will do it.
When New England played Pittsburgh in early December, the Steelers were thought to have a chance because of their strong pass defense, at the time nearly 15 yards a game better than any other team in the league.
So, of course, what better way to make a point for the Patriots than to call passes on 33 consecutive offensive plays from the middle of the second quarter until late in the fourth, taking a lead that was 14-10 to the final score of 34-13.
And when Jacksonville and San Diego, in the playoffs, aligned their defenses to take away Tom Brady's long passing game, the Patriots simply went to a short-pass game instead. After averaging more than 12 yards a completion during the regular season, Brady averaged fewer than 10 in the two playoff victories.
Of his 26 completions against Jacksonville, only two were longer than 15 yards. Of his 22 completions against San Diego, none was longer than 18 yards.
The Patriots can go for the kill in a hurry. They also can kill with a thousand cuts. And when they find something that works, they're not so loaded with ego that they find it necessary to look for something else. If you can't stop them, they'll just keep doing the same thing until you can.
"Josh (McDaniels, the offensive coordinator) does a great job putting guys in position to make plays," said wide receiver Donte Stallworth, invoking an old cliché that, in the Patriots' case, rings true: "We just take what the defense gives us."
The Patriots took enough this year to average 36.8 points and 411.3 yards a game. That was more than eight points and 40 yards more than the second-best teams in those categories.
New England's versatility may be even more impressive than the two four-time champions -- Pitsburgh and San Francisco -- but the pattern is the same. As the dynasty matures, the offense becomes much more potent.
In the '70s, Pittsburgh was forced to re-invent itself when rules changes in 1978 opened up the passing game. The Steelers won Super Bowls in the 1974 and 1975 seasons with a running game and they won Super Bowls in the 1978 and 1979 seasons with a passing game.
Pittsburgh rushed for 398 yards in its first two victories while passing for 286. In its last two, Pittsburgh rushed for 150 yards and passed for 600.
San Francisco made a breakthrough in 1981 with a team that controlled the ball with short passing and strong defense, although Joe Montana got a lot more attention than the defense. The 49ers never really were recognized for their defense, in fact, but their first Super Bowl team ranked No. 2 in the league in defense and only No. 13 in offense.
By 1989, when the 49ers won for the fourth time, they had emerged as an offensive power. With Montana at the height of his game, San Francisco set a Super Bowl record following the '89 season by scoring 55 points against Denver in XXIV. In 1981, the 49ers averaged 11.5 yards per completion. In 1989, they averaged 13.5.
When New England won its first Super Bowl following the 2001 season, the Patriots relied heavily on defense and a conservative offensive approach because Tom Brady was in only his first season as a starter. The playbook has expanded considerably since then.
"It's evolution," said wide receiver Troy Brown, the Patriots' senior player. "You have to change. If we were still in the same position we were in (in 2001) and running the exact same plays, we wouldn't be here."
Brady's maturation, of course, has made it possible for McDaniels to add to the playbook and create a scheme in which players have so many different roles, and it can be unsettling for a defense to prepare for that.
McDaniels said Brady "has the capacity to learn a ton of information" each week, allowing the offensive approach to change significantly.
"He has the capacity to take that in and make it work on the field," McDaniels said. "The foundation and the system is very much the same (as it was in 2001) as far as the terminology is concerned. (Brady) can obviously handle a tremendous amount of information and we can put a lot on his shoulders. This guy can take a lot of information in a game plan in a specific week about a specific team, and really operate at a high level."
At the same time, New England's players, especially those filling the so-called "skill" positions, have a heavy learning workload every week.
"It's a bit of variety," said Heath Evans, the fullback. "Sometimes, you'll see me at wide receiver and other times you'll see me at tailback and everywhere else."
Kevin Faulk is ostensibly the third-down back but he said he has lined up at "five or six" different spots this year; he was third on the team in both rushing and receiving.
And the wide receivers, Randy Moss and Wes Welker, Stallworth and Jabar Gaffney, are almost all interchangeable. They can play flanker, split end or slot receiver.
"We can do a lot of different things with those guys, and that's what we think is difficult to defend," said McDaniels. "If you don't know where they're at, it's difficult to defend them. We have a lot (of packages), and they're all for a reason. We all felt from the beginning of the season on, that our depth at the skill position spots was one of our strongest points that we could possibly have coming into the season.
"To be able to use those guys and get them all involved in the game is an advantage for us. We want them to be involved in the game because to go a half without putting one of those guys on the field and giving them an opportunity to make a good play, I don't know what good we're doing."
Even tight end Kyle Brady, known mostly for his blocking, occasionally will slip out and become a deep receiver. The Patriots opened the AFC Championship Game against San Diego with a deep ball for Brady. It fell incomplete, but it sent a message.
"You just kind of have to stay up with everything," Brady said, calling the Patriots' offense "very dynamic."
"It changes each week," he said. "There are only so many running plays and passing plays, but the manner in which you get to those plays can change."
Which might be why Steve Spagnuolo, the Giants' defensive coordinator, says, "Nobody's going to re-discover any special defenses now." His philosophy sounds the same as New England's: You don't want to put your players in any situation that they can't handle.
So far, it seems, the Patriots haven't found any situation they can't handle, and the versatility of their players is a big reason for that.
Veteran NFL writer Ira Miller is a regular contributor to NFL.com