Perimeter of contours as a function of their radius of gyration for two prokaryotic and two eukaryotic genotypes, including WT P. aeruginosa bacteria (yellow circles) and a hyperpilated pilH P. aeruginosa mutant (blue squares) that individually move faster, and MDCK cells (red diamonds) and MCF-7 human breast cancer cells (purple stars). Here we separately analysed the complete perimeter and accessible external perimeter of the contours (Extended Data Fig. 3 ). We found that the experimental data for all four genotypes collapsed onto lines with slopes of approximately 7/4 and 4/3 for the two different perimeter measurements. The flow fields produced by a numerical model of active fluids ( Methods ) generated vorticity contours with a power-law dependency in close agreement with that observed in the experiments. The perimeter and radius of gyration is normalized by the radius of gyration of the largest vorticity cluster in their respective systems R g,max ( Methods ).
