A method is described of mating composite structures by means of straps, thus avoiding the use of through-structure fasteners and the need to drill holes through the composite structure. The lighting arrangement includes a plurality of light emitting diodes of at least two groups, the light emitting diodes being arranged on a surface element, wherein each group includes a light emitting diode or a plurality of light emitting diodes of the same kind and light emitting diodes of different groups are of different kinds. The display unit includes a screen. Feature shapes may be a grid formed with line sizes similar to those employed to form conductive interconnects, so that all features on the substrate have essentially the same line width.