High Quality Content by WIKIPEDIA articles! The bullroarer, rhombus, or turndun, is an ancient ritual musical instrument and means of communicating over extended distances. It dates back to the Paleolithic period, being found in Ukraine dating from 17,000 B.C. It is found in Europe, Asia, the Indian sub-continent, Africa, the Americas, and Australia. In ancient Greece it was a sacred instrument used in the Dionysian Mysteries and is still used in rituals worldwide. Along with the didgeridoo, it is prominent technology among Australian Aborigines, used in ceremony across the continent. The bullroarer is sometimes used as a means of demonstrating the Doppler effect in sound waves. As the instrument travels around its circular path, its perceived pitch will, to a third party, appear to rise and fall as it moves closer and farther away, respectively.