Meta-Mirror (IMAGE) Duke University Caption This 'metamaterial' controls which way sound reflects off of it by controlling the sound wave's speed and amplitude through the channels and shapes built within it. Credit Steve Cummer, Duke University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.