In 1976 Colonel John Boyd presented "Patterns of Conflict", a study outlining a number of historical matchups in which the victor was able to disrupt the "observation-orientation-decision-action time cycle or loop" of their enemy. This, he stated, made them "appear ambiguous (unpredictable) thereby generate confusion and disorder". His primary example of such action was the Blitzkrieg, where highly mobile forces were quickly concentrated at small points and then used to force a number of simultaneous thrusts through the front. Blitzkrieg aimed at forcing the enemy into a continuous battle of maneuver instead of an outright fight, bypassing any strongly defended areas and extending into their rear. In order to guarantee supply movement and avoid being encircled, the enemy is forced to retreat in an attempt to reform continuous defensive lines.