The perceived lateral position of a transmitted beam, upon propagating
through a slab made of homogeneous, isotropic, dielectric material at an
oblique angle, can be controlled through varying the velocity of the slab. In
particular, by judiciously selecting the slab velocity, the transmitted beam
can emerge from the slab with no lateral shift in position. Thereby, a degree
of concealment can be achieved. This concealment is explored in numerical
calculations based on a 2D Gaussian beam
