  We investigate a class of mass deformations that connect pairs of 2d (0,2)
gauge theories associated to different toric Calabi-Yau 4-folds. These
deformations are generalizations to 2d of the well-known Klebanov-Witten
deformation relating the 4d gauge theories for the C^2/Z_2 x C orbifold and the
conifold. We investigate various aspects of these deformations, including their
connection to brane brick models and the relation between the change in the
geometry and the pattern of symmetry breaking triggered by the deformation. We
also explore how the volume of the Sasaki-Einstein 7-manifold at the base of
the Calabi-Yau 4-fold varies under deformation, which leads us to conjecture
that it quantifies the number of degrees of freedom of the gauge theory and its
dependence on the RG scale.
