  Chemical design of block copolymers makes it possible to create polymer
vesicles with tunable microscopic structure. Here we focus on a model of a
vesicle made of smectic liquid-crystalline block copolymers at zero
temperature. The vesicle assumes a faceted tetrahedral shape and the smectic
layers arrange in a stack of parallel straight lines with topological defects
localized at the vertices. We counted the number of allowed states at $T=0$.
For any fixed shape, we found a two-dimensional countable degeneracy in the
smectic pattern depending on the tilt angle between the smectic layers and the
edge of the tetrahedral shell. For most values of the tilt angle, the smectic
layers contain spiral topological defects. The system can spontaneously break
chiral symmetry when the layers organize into spiral patterns, composed of a
bound pair of $+1/2$ disclinations. Finally, we suggest possible applications
of tetrahedral smectic vesicles in the context of functionalizing defects and
the possible consequences of the spiral structures for the rigidity of the
vesicle.
