Acoustic metamaterial (image) ETH Zurich Department of Physics Share Print E-Mail Caption The experimental sample used for establishing the presence of fragile topological states. The Lego figure is added for scale. Credit ETH Zurich/D-?PHYS Huber group Usage Restrictions None Share Print E-Mail 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.