To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Video 2 Movie S2. Defections of small islands caused by traction forces. Comparison of images recorded 10 min apart reveals minute movement of the second small island from the top just before the cell occupies that island. Fibroblasts probe substrate rigidity with filopodia extensions before occupying an area Stephanie Wong, Wei-Hui Guo, and Yu-Li Wang PNAS. 2014. DOI: 10.1073/pnas.1412285111 Download Original Video Browse All Videos »