Chameleon turquoise, and purple. Chameleon skin has a superficial layer which contains pigments, and under the layer are cells with guanine crystals. Chameleons change colour by changing the space between the guanine crystals, which changes the wavelength of light reflected off the crystals which changes the colour of the skin. Colour change in chameleons has functions in camouflage, but most commonly in social signaling and in reactions to temperature and other conditions. The relative importance of these functions varies with the circumstances, as well as the species. Colour change signals a chameleon's physiological condition and intentions to other chameleons. Chameleons tend
Military camouflage and impressionism also influenced the development of camouflage as they dealt with disrupting outlines, abstraction and colour theory. The French established a "Section de Camouflage" (Camouflage Department) at Amiens in 1915, headed by Lucien-Victor Guirand de Scévola. His "camoufleurs" included the artists Jacques Villon, André Dunoyer de Segonzac, Charles Camoin and André Mare. Camouflage schemes of the First World War and Interwar periods that employed dazzle patterns were often described as "cubist" by commentators, and Picasso claimed with typical hyperbole "Yes, it is we who made it, that is cubism". Most of the artists employed as "camoufleurs" were traditional representative