  We study d-wave Fermi surface deformations (dFSD), the so-called Pomeranchuk
instability, on bilayer and infinite-layer square lattices. Since the order
parameter of the dFSD has Ising symmetry, there are two stacking patterns along
the c axis: (+,+) and (+,-). We find that, as long as the c axis dispersion is
finite at the saddle points of the in-plane band dispersion, the (+,-) stacking
is usually favored independently on the details of interlayer coupling,
yielding no macroscopic anisotropy. The dFSD provides unique spontaneous
symmetry breaking that is self-masked in layer materials.
