 The illustration shows a rectangular crossbow formation with each circle representing one man.In the front is a line labeled "shooting crossbows" (發弩) and behind that line are rows of crossbowmen, two facing right and two facing left, and they are labeled "loading crossbows" (張弩).The commander (大將軍) is situated in the middle of the formation and to his right and left are vertical rows of drummers (鼓) who coordinate the firing and reloading procedure in procession