R. Williams discovered in 1963 that application of an electric field to a thin layer of nematic liquid crystal (NLC) causes the formation of a lattice of cylindrical lenses within the liquid crystal material. For small a.c. potentials (5-10 volts) the minute deformation takes place regardless of whether the layer was originally of homogeneous or homeotropic alignment. A system of largely parallel striations is observed under a polarizing microscope. The line textures are called Williams domains after their discoverer. The stationary pattern usually gives way to turbulence at higher voltages, thus producing dynamic light scattering. The far-field diffraction pattern of light transmitted through these domains is similar to that from a phase grating. The diffraction pattern consists of equally spaced fringes.