Fangio’s Either/Or concepts are some of the best aspects of the defense.
What is does is handling formations making sure you’re not a
not taken advantage of any formation because of motion.
So, the secondary plays either Cov-4 or Cov-2 based on the
release of the #2 receiver, if it is vertical it's 4, if it is inside
or outside it's Cov-2 ... so, it could be Cov-2 on one side
or both, it could be Cov-4 on one side or both
This is one is a pressure from the base defense, there 3-4
both OLBer rush, and you see the Dlmen are not gap-and-a-half-ing it
the take one gap with the nose has his choice.
The two linebackers also read but the curl zone for Cov-2 and for
Cov-4 is not that different so it's not noted in the diagram
The thing is though it looks the same every time the QB does not know
what the defense is in until after the snap and because of that
does not know where the windows are until after the snap.
You see the Rams with this pressure a lot..both OLBers rush
you'd never know this call---there is no way to know because
if it were Cov-6, Cov-8 or this it could look the same but
to our eyes.