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
Dazzle camouflage patterns of] animals". The British Army inaugurated its Camouflage Section for land use at the end of 1916. At sea in 1917, heavy losses of merchant ships to Germany's unrestricted submarine warfare campaign led to new desire for camouflage. The marine painter Norman Wilkinson promoted a system of stripes and broken lines "to distort the external shape by violent colour contrasts" and confuse the enemy about the speed and dimensions of a ship. Wilkinson, then a lieutenant commander on Royal Navy patrol duty, implemented the precursor of "dazzle" beginning with the merchantman SS "Industry". Wilkinson was put in charge of