Stages in the evolution of SN ejecta interacting with a colliding wind shell oriented to the SN progenitor (model B1). The columns show snapshots at times t = 300, 400, and 450 days. Each row shows different quantity, from top to bottom: density ρ, radial velocity u_r, and polar velocity u_θ. The remaining quantities are shown in Fig. 5. Animated version of the two combined figures is available as the movie B1.