Snapshots displaying isosurfaces where the mass fraction of ⁵⁶Ni plus n-rich tracer X equals 3% for model W15-2-cw (top row), L15-1-cw (second row), N20-4-cw (third row), and B15-1-pw (bottom row). The isosurfaces, which roughly coincide with the outermost edge of the neutrino-heated ejecta, are shown at four different epochs starting from shortly before the SN shock crosses the C+O/He composition interface in the progenitor star until the shock breakout time. The colors give the radial velocity (in units of km s^-1) on the isosurface, with the color coding defined at the bottom of each panel. In the top left corner of each panel we give the post-bounce time of the snapshot and in the bottom left corner a yardstick indicating the length scale. The negative y-axis is pointing toward the reader. One notices distinct differences in the final morphology of the nickel-rich ejecta of all models, which arise from their specific progenitor structures.