  It is argued that there exist natural shell model spaces optimally adapted to
the operation of two variants of Elliott' SU3 symmetry that provide accurate
predictions of quadrupole moments of deformed states. A selfconsistent
Nilsson-like calculation describes the competition between the realistic
quadrupole force and the central field, indicating a {\em remarkable stability
of the quadruplole moments}---which remain close to their quasi and pseudo SU3
values---as the single particle splittings increase. A detailed study of the
$N=Z$ even nuclei from $^{56}$Ni to $^{96}$Cd reveals that the region of
prolate deformation is bounded by a pair of transitional nuclei $^{72}$Kr and
$^{84}$Mo in which prolate ground state bands are predicted to dominate, though
coexisting with oblate ones,
