20 Electrons
Gamma=100
T=3.04 10^9 T_OM
no initial rotation

T is way above orientational
melting (T=0.68 10^9 T_OM!)
So relative rotation of the
two shells is possible.
Note that rotation starts
"spontaneously".

For an explanation, see the case of
five times lower T (Gamma=500)

20 Electrons, Gamma=500 | 19 Electrons, Gamma=500 | 19 vs 20 Electrons, Gamma=500
19 Electrons, 1 pinned, Gamma=500 | 19 Electrons, 1 pinned, Gamma=160 | 19 Electrons, 1 pinned, Gamma=100
19 (1 pinned ) vs 20 Electrons, Gamma=500 | 19 Electrons free vs. pinned, Gamma=500 | 19 Electrons (1 pinned), Gamma=500 vs. 160
19 Electrons, Gamma=500, zero initial rotation | 20 Electrons, Gamma=500, zero initial rotation | 20 Electrons, Gamma=100, zero initial rotation