This preset uses a basic thin-film-like effect created using the inverse of interfering sinusoidal plane waves. Taking a modulus of this inverse gives the effect of concentric rings around poles and troughs around zeroes in the plane. This effect is similar to what one would see under raking light between two thin sheets of translucent material that are buckled slightly. The diffraction of light is a function of the spacing between the planes (quarter-wave optics). Areas that are close together reflect shorter wavelengths than areas that are spaced futher apart, and this selectivity is a linear function of the spacing.