sentences:  The three wave hypothesis compares the wave–particle duality to a bevel gear.The gear mechanism was previously considered exclusively artificial, but in 2013, scientists from the University of Cambridge announced their discovery that the juvenile form of a common insect "Issus" (species Issus coleoptratus), found in many European gardens, has a gear-like mechanism in its hind legs.Each leg has a 400 micrometer strip, pitch radius 200 micrometers, with 12 fully interlocking spur-type gear teeth, including filleted curves at the base of each tooth to reduce the risk of shearing.