Publication Date



Technical Report: UTEP-CS-23-08


At present, many living creatures have symmetries; in particular, the left-right symmetry is ubiquitous. Interestingly, 600 million years ago, very fee living creatures had the left-right symmetry: most of them had a gliding symmetry, symmetry with respect to shift along a line followed by reflection in this line. This symmetry is really seen in living creatures today. In this paper, we provide a physical-based geometric explanation for this symmetry change: we explain both why gliding symmetry was ubiquitous, and why at present, it is rarely observed, while the left-right symmetry is prevalent.