"The shotgun formation is a formation used by the offensive team in American and Canadian football. This formation is used mainly for passing plays, although some teams use it as their base formation. In the shotgun, instead of the quarterback receiving the snap from center at the line of scrimmage, he stands farther behind the line of scrimmage, often five to seven yards back. Sometimes the quarterback will have a back on one or both sides before the snap, while other times he will be the lone player in the backfield with everyone spread out as receivers." [Shotgun formation. Wikipedia]
The American football positions diagram example "Shotgun formation (Offense)" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Football solution from the Sport area of ConceptDraw Solution Park.