  Although the free energy of a genome packing into a virus is dominated by
DNA-DNA interactions, ordering of the DNA inside the capsid is
elasticity-driven, suggesting general solutions with DNA organized into
spool-like domains. Using analytical calculations and computer simulations of a
long elastic filament confined to a spherical container, we show that the
ground state is not a single spool as assumed hitherto, but an ordering mosaic
of multiple homogeneously-ordered domains. At low densities, we observe
concentric spools, while at higher densities, other morphologies emerge, which
resemble topological links. We discuss our results in the context of metallic
wires, viral DNA, and flexible polymers.
