Diffuseness ψ (colormap and 90% contour) and level w normalized to origin (blue dotted 1 dB contour) of a 3:2 p=10 superellipse/rectangle of L={4, 6, 8, 12} vertical line sources (dots) using/initialized by equi-angular circular {3, 5, 7, 11} designs, with t-designs and ${\sigma }^2=r_0^D{r}_{\text{a}}^2$ in (a–d), and sources with σ²=1 arranged by solving the Thomson problem in (e–h), compared against a relative radius $\raisebox{1ex}{$x$}\!\left/ \!\raisebox{-1ex}{$x_{\text{max}}$}\right.=\{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.,\raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right.,\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$4$}\right.,\raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$6$}\right.\}$ (orange red, dotted).