  Trirefringence is related to the existence of three distinct phase velocity
solutions (and polarizations) for light propagation in a same wave-vector
direction. This implies that when a trirefringent medium refracts a light ray,
it is split into three rays with different velocities and linearly independent
polarizations. Here a previous investigation [1] is revisited and its results
are generalized to include a broader class of magnetoelectric materials.
Moreover, it is argued that trirefringent media could already be achieved using
present day technologies. Examples are given to support that focused on built
layered media under the influence of applied electromagnetic fields.
