Signal for 11

[The Roamin' Umpire]

FWIW, this is why I like the college mechanic for counting linemen much better than anything else. The H and L don't need to look for R & U to be signalling 11 - they just count linemen on their side of the snapper.

The mechanic, as I've seen it, is: With three, do nothing. With four, put four fingers against your cheek. With two, hold out two fingers. If one wing has two, and the other doesn't have four, you've got a flag.