Growing blood vessels are experts at multitasking. Not only do cells in their walls divide, they must also sprout in new directions while learning to specialize, ultimately becoming part of vein, artery or lymphatic vessels. Prof. Karina Yaniv and her team at the Weizmann Institute of Science set out to learn how the cells juggle these multiple challenges, and they came up with surprising answers that may shed new light on cancer treatment, heart regeneration and other conditions involving blood vessel growth.