First pictures as reference for inter-picture prediction of an incoming moving-picture and second pictures are coded. The method comprises transmitting the packet data and the side information over a dedicated channel during the initial transmission; and transmitting the packet data and the side information over a common channel during the retransmission. The method also avoids the use of expensive reagents and capital intensive distillation equipment. When used to make wrinkle bends, the fixed die section and movable die sections define wrinkle receiving recesses. A width of the step is set substantially equal to a common multiple of \u03bbi{n\u22121} for two or more wavelengths, where \u03bbi is a wavelength and n is a refractive index with respect to the wavelength \u03bbi.