The Notre Dame Box is a variation of the single-wing formation used in American football, with great success by Notre Dame in college football and the Green Bay Packers of the 1920s and 1930s in the NFL. Green Bay's coach, Curly Lambeau, learned the Notre Dame Box while playing for Knute Rockne in the late 1910s. Rockne learned it from Jesse Harper, who learned it from coach Amos Alonzo Stagg. It contained two tight ends, and 4 backs. The formation often featured an unbalanced line where the center (that is, the player who snapped the ball) was not strictly in the center of the line, but close to the weakside.