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A presentation aid can provide both audio and visual assistance simultaneously (as in a digital video recording of an exotic bird singing), audio assistance only (a recording of a Harley-Davidson motorcycle engine), or visual assistance only (a photograph of a person on a surfboard). Traditional aids include the speaker him- or herself, assistants, objects, visual images (maps, photographs and drawings, diagrams), graphs, text-based visuals, and audio and video. Here we take a closer look at each type of presentation aid.