  Core-collapse supernovae, the culmination of massive stellar evolution, are
spectacular astronomical events and the principle actors in the story of our
elemental origins. Our understanding of these events, while still incomplete,
centers around a neutrino-driven central engine that is highly hydrodynamically
unstable. Increasingly sophisticated simulations reveal a shock that stalls for
hundreds of milliseconds before reviving. Though brought back to life by
neutrino heating, the development of the supernova explosion is inextricably
linked to multi-dimensional fluid flows. In this paper, the outcomes of
three-dimensional simulations that include sophisticated nuclear physics and
spectral neutrino transport are juxtaposed to learn about the nature of the
three dimensional fluid flow that shapes the explosion. Comparison is also made
between the results of simulations in spherical symmetry from several groups,
to give ourselves confidence in the understanding derived from this
juxtaposition.
