THE offense (playing from left to right) have succeeded in slipping a back past the defensive right tackle. The two defensive players in front of the rmner were swept aside by the one offensive interferer (with outstretched leg). However, the defensive left tackle (No. 21) sensing perhaps the nature of the play, ran behind his own line, thereby breaking one of the cardinal principles of line play and tackled the runner for a small gain.
Thus, by unorthodox methods, the defense spoiled an offensive maneuver in which every assignment was perfectly carried out.
Harvard vs. Yale 1921.