Evolutionary tracks of the SNR #22 in the shape phase-space for the various explosion models. Uncertainties due to the choice of Z_{ej, thr} are shown as shaded regions. In different parts of the phase space the SNRs are either spherical (S), oblate-spheroidal (OS), prolate (P), or oblate (O). The SNR starts out as a perfect sphere and becomes increasingly prolate over time. The ratio of the two minor axes remains close to one and never falls below 2/3. In the model N10 the SNR remains spherical for longer compared to N1. Similarly the consecutive SN explosions in the model N1×10 restore spherical symmetry.