Simulation of a pedestrian counterflow (IMAGE) American Institute of Physics Caption Simulation of a pedestrian counterflow (red and blue particles, with green arrows denoting instantaneous velocity) confined within a hallway (gray boundary), under conditions of weak social distancing. Credit Gerald J. Wang Usage Restrictions Journalists may use this image only with appropriate credit. License Original 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.