  We report full vector mapping of local magnetization in CeAlSi, a Weyl
semimetal in which both inversion and time-reversal symmetries are broken. The
vector maps reveal unanticipated features both within domains and at their
boundaries. Boundaries between domains form two kinds of walls with distinct
topology and therefore different interactions with Weyl fermions. Domain walls
aligned along the tetragonal axes, e.g. (100), exhibit emergent chirality
forbidden by the bulk space group, while diagonal walls are non-chiral. Within
the domains, we observe that the previously reported set of four easy axes
aligned along the in-plane diagonals of the tetragonal structure actually split
to form an octet with decreasing temperature below the magnetic transition. All
the above phenomena are ultimately traced to the noncollinear magnetic
structure of CeAlSi.
