Consequently, the rule against conclusions provides an exception for conclusions that are (1) based on the perception of the witness and (2) "helpful to a clear understanding of the witness' testimony.' The first requirement adds nothing new to the personal knowledge requirement. The second requirement that the conclusion be "helpful" simply means that expressing what the witness needs to express without using conclusions would be cumbersome and abnormal. This second requirement is certainly satisfied in the brick-throwing example above. Common examples of other lay conclusions that are more conclusionary, but are permitted, are statements such as that a person was "drunk" or that a car was going "thirty-five miles per hour.