Coloured surfaces of rest-mass density 3D distribution, in code units, for the evolved structure of simulation S1 at t ≈ 3000 yr, corresponding to the bottom left panel of Fig. 3. The axis of the jet is in the middle of the XZ plane, and the latter propagates along the Y-axis (triad visible in the bottom left of the image) and from left to right; the surfaces show the shocked ejecta interacting with the jet flow, while the nearly transparent red layer surrounding the shocked ejecta outlines the shocked jet region.