Before revision: Interacting, self-propelled particles such as motile epithelial cells can dynamically URLanize into large-scale patterns. In such living systems, cell number and density can vary dramatically over time due to proliferation, which is not commonly considered in other active matter systems. As a consequence, it remains challenging to determine individual and collective phases over varying populations sizes without a priori information.
After revision: Interacting, self-propelled particles such as motile epithelial cells can dynamically URLanize into complex multicellular patterns, which are challenging to classify without a priori information.