Researchers have uncovered the mathematical and biological mechanism behind the interdigitation at cell boundaries. These structures are commonly found in epithelial cells in tissues such as the kidneys and nasal glands, and is proposed to facilitate paracellular transport. The team found that the boundary dynamics show a 'push-and-pull' movement that exhibits scaling that can be reproduced by the Edward-Wilkinson model. They also found that myosin may be responsible for the nature of the dynamics.