Active camouflage the surface, so when marine animals are seen from below, they appear darker than the background. Some species of cephalopod, such as the eye-flash squid and the firefly squid, produce light in photophores on their undersides to match the background. Bioluminescence is common among marine animals, so counterillumination may be widespread, though light has other functions, including attracting prey and signalling. Color change permits camouflage against different backgrounds. Many cephalopods including octopuses, cuttlefish, and squids, and some terrestrial amphibians and reptiles including chameleons and anoles can rapidly change color and pattern, though the major reasons for this include signalling, not
Military camouflage smaller shapes with dithering; this softens the edges of the large scale pattern, making the underlying objects harder to discern. Pixellated shapes pre-date computer aided design by many years, already being used in Soviet Union experiments with camouflage patterns, such as "TTsMKK" developed in 1944 or 1945. In the 1970s, US Army officer Timothy R. O'Neill suggested that patterns consisting of square blocks of colour would provide effective camouflage. By 2000, O'Neill's idea was combined with patterns like the German "Flecktarn" to create pixellated patterns such as CADPAT and MARPAT. Battledress in digital camouflage patterns was first designed by the