Before revision:  As such, collisions can be considered URLanizing centers, for example, in intracellular actin waves .
After revision:  We exemplify our findings based on a model of intracellular actin waves. As biological cells are inherently mass-conserved systems, our results provide a key concept to understand the ubiquitous occurrence of actin waves in cells, explaining why they are so common, and why their dynamics is robust and long-lived .