Science Daily  March 7, 2019 To break the law of reflection with sound waves, an international team of researchers (Finland, USA – Duke University) designed a meta-mirror out of plastic with precisely etched channels on the surface of the metamaterial. Between the meta-mirror’s shape and the depth of its channels, the interference pattern results in the sound wave reflecting in a desired direction without any of its energy being absorbed or scattered in an unwanted direction. In demonstration the device reflected a soundwave traveling directly toward it at 3,000 Hertz and perfectly reflects it at an angle of 70 degrees. […]