If you are a chalkboard football fan, NFP's Matt Bowen just became your favorite NFL sports writer:
In the past we have discussed teams such as New England who use multiple personnel groupings and formations. Indy, on the other hand, is just the opposite. They rely on their "Ace" or 212 personnel (2 WR, 1 RB, 2 TE) and "Posse" or 311 personnel (3 WR, 1 RB, 1 TE). Nearly the entire playbook is run with these two personnel groupings on the field. Yes, there is some window dressing involved to align in different formations, but at the end of the day this is what you see from Indy.
Matt then goes into detail explaining the Colts' top passing routes: the china/dig and 4 verticals. It's a must read for people who love charts, diagrams, squiggly lines, and simple explanations that accurately define just how excellent the Colts offense is.