is a list of innovations Stagg introduced to American football. Where known, the year of its first use is annotated in parentheses. Stagg is noted as a 'contributor' if he was one of a group of individuals responsible for a given innovation. Ends-back formation (1890) Reverse play (1890) 7–2–2 defense (1890) First indoor game (1891) First book on football with diagrams (1893; with Minnesota's Henry Williams) First intersectional game (1894) center snap (1894; John Heisman and Walter Camp claimed to have invented it in 1893) onside kick (1894; possibly contributor) huddle (1896) quick kick (1896) Short punt (1896) Spiral snap (1896; contributor alongside Walter Camp, George Washington Woodruff and Germany Schulz) line shift (1897) placement kick (1897; Stagg believed Princeton used it earlier) lateral pass (1898) tackling dummy (1899) unbalanced line (1900) Notre Dame Box (1905) varsity letters (1906) Statue of Liberty play (1908) uniform numbers (1913) T formation (contributor) forward pass (contributor alongside Eddie Cochems and Walter Camp) man in motion sleeper play quarterback keeper delayed buck linebacker position hip pads numerical designation of plays padded goalposts end-around Coaching tree In addition to Stagg's championships and innovations, another aspect of his legacy is in his players and assistant coaches who went on to become head football and basketball coaches at other colleges and universities across the countries. Played under: Walter Camp Assistant coaches who became head coaches: John Anderson: Knox (1917), Rice (1918) (also played under Stagg at Chicago) Hugo Bezdek: Oregon (1906, 1913–1916), Arkansas (1908–1912), Penn State (1918–1929), Cleveland Rams (1937–1938) (also played under Stagg at Chicago) Fritz Crisler: Minnesota (1930–1931), Princeton (1932–1937), Michigan (1938–1947) (also played under Stagg at Chicago) Ira Davenport: Columbia (IA) (1920–1921) Leo DeTray: Ole Miss (1912), Knox (1915–1916) Clarence Herschberger: Lake Forest (1902–1904) (also played under Stagg at Chicago) Harlan Page: Butler (1920–1925), Indiana (1926–1930), College of Idaho (1936–1937) (also played under Stagg at Chicago) James M. Sheldon: Indiana (1905–1913) (also played under Stagg at Chicago) Frederick A. Speik: Purdue (1908–1909) (also played under Stagg at Chicago) Amos Alonzo Stagg Jr.: Susquehanna (1935–1954) (also played under Stagg at Chicago) Paul Stagg: Moravian (1934–1936), Springfield (1937–1940), Worcester Tech (1941–1946), Pacific (1947–1960) (also played under Stagg at Chicago) Wayne Hardin: Navy (1959–1964), Philadelphia Bulldogs (1966), Temple (1970–1982) (also played under Stagg at Pacific) Larry Siemering: Pacific (1947–1950), Arizona State (1951), Calgary Stampeders (1954) Former players who went on to become head coaches W. J. Keller: