Many tissues are dynamical entities that need to adapt their shape over time (left). Adaptation involves collective movement of cells at the tissue-scale, in which cells align with each other and with the direction of tissue flow. This state is faithfully described as a long-range nematic phase indicated by black lines (middle). Yet at increased resolution, at the cell scale, shape order is dominated by an area-filling hexatic phase, dominated by the properties of individual cells (right). As shown throughout this report, cell-specific as well as external parameters control the length scale at which collective behavior toward a nematic phase is observed, that is essential for tissue function and integrity.
