The contrast in styles is extreme. The Patriots' offense likes to throw, often spreading the field with three and four receivers. The Jaguars will take their shots through the air, but would generally prefer to grind it out. The Patriots' defense plays a 3-4 alignment and its schemes are complex and ever-changing. The Jaguars are a 4-3 team that generally keeps things simple, focusing on assignment-sound football. One head coach wears a gray hoodie, while the other has paced the sideline in a suit, and other times dons a leather jacket. When the Patriots and Jaguars knock helmets Saturday night in the AFC divisional round at Gillette Stadium, it will be two distinct worlds colliding. Expect to hear a loud thud, because if there is one obvious similarity between the clubs, it's that both take pride in physical play. We take a position-by-position look at the teams, and let you decide who has the edge. (Text by Mike Reiss, Globe Staff)