One of the most interesting teams in the country, San Diego State just finished both 10-3 and vaguely bummed. Its head coach wrapped up a palpitating 42-35 Armed Forces Bowl loss to Army by observing, "I never thought I'd be disappointed with 10 wins." A sparkling 32-9 record across three seasons has spiked the expectation meter and coaxed others to pluck Aztecs coaches, with two major assistants just lured elsewhere.

San Diego State has a further distinction, though: It's a window to the long arc of college football. As it relishes its 20th-century I-formation offense and its two straight 2,000-yard rushers (Donnel Pumphrey in 2016, Rashaad Penny this season ), it's both brutish and "old school in a young-school game," as offensive coordinator Jeff Horton put it in October. That can seem amusing in palmy San Diego, as special teams coordinator Bobby Hauck, just hired as Montana's head coach, did remind, "The Navy SEALs are based here. The U.S. Marine Corps. We've got some toughness in this town!"

But in a town that knows a tide, San Diego State operates against the tide of the spread offense that has spread across the land. As said Mike Leach, the Washington State coach and spread pioneer, "It's still taking off."

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"Oh, eventually guys like us might have to go to the spread, because of recruiting," Rocky Long said in October, seven seasons into his work as San Diego State's head coach. "It's already happening in the NFL. They're taking these first-round draft-choice guys that are spread guys. And so they struggle. So what do the teams do? They go to the spread.

"It happened with the L.A. Rams. They take [Jared] Goff with the first pick . . . and they put him in a pro-type offense [in 2016] and he's horrible. But this year, they're a spread [offense] and he's having a great year, because he's never been trained in the other offense."

The spread has spread to the top (the NFL) and from the bottom (high schools). A term used rather broadly, the spread offense most commonly refers to a formation that employs three or more pass catchers to stretch the defense both horizontally and vertically. It is sometimes, but not always, a pass-heavy approach, and its most important characteristic is that it forces the defense to cover more of the field, as opposed to overpowering the opponent in small spaces as in a more traditional offense — like the I-formation San Diego State uses.

Long looks up and sees the New England Patriots "in the spread 80 percent of the time," and he looks down and sees: "Since very few teams run the ball in high school anymore, eventually we might have to adapt to what we're recruiting. There's more and more high schools going to the spread, which means there's more and more spread quarterbacks, spread receivers, spread running backs. Offensive linemen are different, too: They're all lateral-step and sumo-wrestle you. They don't come off the ball and knock you backward anymore. So if those are the guys you're recruiting, you're going to have to adjust your program to the best players you can get."

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The spread of the spread has enabled Leach to say, here in late 2017, "I don't really care, but what's kind of funny is we haven't changed what we do for 25 years, but there's sure a lot of people coming to the party, for all the maligning we heard on the front end."

Then, of the lingering skeptics: "They don't want to tell you what's a better way. They don't have any specifics. They just want to attack the idea because they aren't creative enough to come up with something."

By now, everyone around the sport knows the spread comes in variations, from Leach's to Chip Kelly's to Oklahoma's to Urban Meyer's and all the way over to Bill Belichick's. Yet, as Leach explains, it all distills to this: "You've got two resources: personnel and space. You want to utilize both as much as you can."

In that vein, he said, "Honestly, to me, the very first spread-run offense was the wishbone." Explaining: "It was a spread from the standpoint that it went sideline to sideline. And it also attacked downfield, because the pitch could happen downfield. And, perhaps most important, every skill player touched the ball."

The art of frazzling the defense by concerning it with bountiful threats differs from olden days when, as Leach said, teams would "only throw to two receivers, with one running back getting the ball."

Emblematic of the era, the four College Football Playoff teams had populous involvement, even though you wouldn't deem them spread extremists. Clemson had three rushers with 646-plus yards (counting the quarterback), Oklahoma four with 310-plus (counting the quarterback), Georgia three with 597-plus and Alabama eight with triple-digit yardage and three with 549-plus (counting the quarterback). Clemson had three receivers with 46-plus catches and nine in double digits, Oklahoma five with 23-plus catches and 10 in double digits, while Georgia and Alabama kept their balance largely to rushing, with Georgia 110th nationally in passing and Alabama 86th, and with Alabama's Calvin Ridley out-catching his nearest teammate 55-14.

"To me, the biggest fallacy that's existed and still exists and people still believe it, which is intellectually dishonest, the notion that if I throw it 50 percent of the time and I run it 50 percent of the time, I'm balanced," Leach said. "There's nothing balanced about it. . . . I think the biggest misconception is that people are into styles. There's good football plays, and there's bad ones. There's ones that utilize space and attack, and there's ones that don't."

Meanwhile, San Diego State plies its anomaly. Its coaches confess they value time of possession, while spread teams don't. They cite the importance of playing keep-away against foes with gaudier offenses, and they had two wins over Pacific-12 Conference foes to show for it this season, Stanford and Arizona State among their victims.

They note a slight recruiting boon of being different, so running backs take a look, as do 240-pound defensive linemen who don't have to bulk up to 300 with all the slanting and stunting in Long's defense, of which you can count Leach as an admirer. They're a bit more like the NFL, they can tell young men — or at least a good chunk of the NFL. If a running back opts to go elsewhere, Horton might tell the guy, "If you don't come to our school, do me a favor: At least go somewhere where they run the football, because you're too good a running back just to go in there and run sideways all the time, or whatever."

Even so, they do live with the wrinkles of the encroaching spread, and one of those is the inconvenience of practicing against it. It helps that, as said defensive coordinator Danny Gonzales, just lured to Arizona State: "Most of the kids we recruit are from spread offenses, because it's kind of all that's out there anymore. So they have an idea of how to perform it as freshmen when they haven't really been trained into what we do on offense, so we get a fairly decent look."

Since spread has spread from "Pop Warner on up," Horton said, "kids don't know how to take a snap nowadays. They don't know how to call a play. And you see the trickle-down." You also see the glaring need for "athletes that can tackle well in space," Gonzales said.

Long, a hardy 67, can spot the wave like a keen San Diegan. He frets that it becomes "more of a talent game," tilted toward the talent-stocked.

Leach looks around the NFL, lists teams using spread and says, "I didn't know that Pittsburgh ever would, but Pittsburgh spreads it out." He saw a New England-Atlanta Super Bowl full of spread and said: "I wouldn't say it was eye-opening, but they both threw it like crazy, they both went to the Super Bowl, and it was a great game. . . . I think it's really taking over the NFL in a big way." And that would seem a last frontier.