The anticipatory period leading up to a performance of any sort is difficult for most performers, but there is a particular challenge involved in waiting to perform an act that is to some degree extemporaneous, and battle rap is a rather harrowing mix of the extemporaneous and premeditated.

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Her hours-long lecture is a mesmerizing romp of set pieces and extemporaneous patter, jumping from Christopher Columbus, to Egyptian pyramids, to the Great Wall, to Bill Gates.

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Certainly a great deal of preparation goes into a debate performance, but most of what a politician says up there on the stage is extemporaneous.

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