Instead of saying something like 962 like you would in a passing tree, we would say something like “63.” The first number would be the number of the protection and the second number would be the route combination. It would mean these receivers have these combinations of routes. One may have the slant, one may have the post, one may have the swing, etc. So, if you wanted to change the route, you just change a number. In our system, you might say “63 F Post” or “63 F Wheel.” It’s not as wordy as a passing tree. One thing I think we did well was reduce the verbiage of the play to make the call as short and as quick as possible. For example everyone runs the “stick” concept, with a vertical outside, an option route by the inside receiver and flat route by the running back. I’ve been at places where there are a ton of verbiage and an episode of charades to signal in the stick route.