有些模仿實在太真實了，聽者很難分辨得出實物及模仿音效，如火車警笛

出處: "Great Northern Train, Four Miles West of Minot, North Dakota" 1912?. The Northern Great Plains, 1880-1920: Photographs from the Fred Hultstrand and F.A. Pazandak Photograph Collections from North Dakota State University, Library of Congress/Ameritech collections.