  Following the RG flow of an N=1 quiver gauge theory and applying Seiberg
duality whenever necessary defines a duality cascade, that in simple cases has
been understood holographically. It has been argued that in certain cases, the
dualities will pile up at a certain energy scale called the duality wall,
accompanied by a dramatic rise in the number of degrees of freedom. In string
theory, this phenomenon is expected to occur for branes at a generic threefold
singularity, for which the associated quiver has Lorentzian signature. We here
study sequences of Seiberg dualities on branes at the C_3/Z_3 orbifold
singularity. We use the naive beta functions to define an (unphysical) scale
along the cascade. We determine, as a function of initial conditions, the scale
of the wall as well as the critical exponent governing the approach to it. The
position of the wall is piecewise linear, while the exponent appears to be
constant. We comment on the possible implications of these results for physical
walls.
