daf bit: Yoma 55

[cellio]

After slaughtering the bull on Yom Kippur, the blood was collected (as for all offerings) and the kohein gadol (high priest) sprinkled it -- usually this is done on the altar, but in the case of the Yom Kippur offering, on the ark. The mishna says that he sprinkled once upward and seven times downward (the gesture is described as "like a whip"), and that he counts the sprinklings out loud: "one, one and one, one and two" and so on up to "one and seven". Why this formulation? So that he will not miscount; if he just said "one, two, three..." then he might get to seven and stop, but the first one was the upward one so he's still one short on the downward ones. Therefore, he counts the upward sprinkling ("one") along with every downward one ("one and one", etc). (55a)