Example light curves of Groups A and S stars. Left column: Group A. From top to bottom: R Aur (bumps in the ascending branch), T Cas (double-peaked maximum), and U Her (abrupt change in the slope of the ascending branch). Right column: Group S. From top to bottom: S CrB (quasi-sinusoidal light curve), U Cen (slight asymmetries only in some of its cycles), and RR Lib (gaps in the light curve prevent us from identifying asymmetries with certainty).