A body for a flow meter for measuring the flow velocity andor the volumetric through-flow of fluids. The optical device has a textured surface having a relief structure finer than a human eye resolution but large enough not to exhibit diffraction effects. The lighting fixture has a housing with a perimetrical wall. At the end of the other arm is a dent pusher plate. The resulting pigment can be used in any application for which pearlescent pigments have been heretofore used such as, for example, in plastics, paints, inks, cosmetic formulations, coatings including solvent or waterborne automotive paint systems, powder coatings, inks and agriculture foils, for the laser-marking of papers and plastics. Absent use of the present method, these stranded messages would not be routed to their original destinations.