Top: illustration of ejecta and radiation properties for the shuffled-shell model s15p2. From upper to lower panels, we show the profiles versus velocity for the mass fraction of H, He, O, Ca, and Fe, their ionization state (zero for neutral, one for once ionized etc.; see also Table 2), and the formation regions for Na I D, [O I] λ 6364, Hα, He I 7065 Å, and [Ca II] λ 7291. The quantity ∫ ξ d log V is the line equivalent width, which here is normalized to unity for visibility.