Colloid Crystal (IMAGE) University of Konstanz Caption If the monolayer of a colloid crystal (blue pellets) slides over an optical grid (orange), friction can disappear entirely. This is because the particles avoid the recesses and move along the ridges of the optical grid. Credit Image: Thorsten Brazda 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.