Correlation of the peak energies of all doubles for a black hole with spin ﹩a=0.5﹩ seen at an inclination of ﹩i=82\buildrel{\circ}\over{.} 5﹩ (﹩h=5\,{r}_{{\rm{g}}}﹩, ﹩\beta =0.5﹩). The different marker types (and colors in the online version) highlight the values from different caustic crossing angles.