Leopold Grinberg of Brown University and an international team of researchers have used three of the world's fastest supercomputers to create a detailed and sophisticated model of clot formation in an aneurism—a bulging of a vessel wall as it fills with blood. Joseph A. Insley and Michael E. Papka, at the Argonne Leadership Computing Facility (ALCF) worked with Leopold's team to produce these stunning visualizations on the various phenomenon influencing the development of an aneurism.