Travelling Bands (IMAGE) Sissa Medialab Caption In a model of self-propelled particles aligning with their topological neighbors, one observes the formation of traveling bands (in green), typical of discontinuous transitions. The particle colors encode their orientations. Credit Material provided by the author of the paper, Julien Tailleur Usage Restrictions No restrictions. License CC0 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.