Curl-Flat is possibly the best play in football. It is a horizontal stretch play designed to put the defensive Flat player in a bind of trying to cover both the Curl and the Flat route. If the play is properly executed, the Flat player will be unable to do both. Curl-Flat is a concept that has been around for quite a while and it has stood the test of time. Its cruel effectiveness is not hindered in any way by its familiarity; rather, the design of the play makes it almost impossible for Cover 3 defenses to stop, even if they practice against it extensively.