 As a camouflage expert during the Second World War, Cott likened the functions of military camouflage to those of protective coloration in nature. The three main categories of coloration in his book Adaptive Coloration in Animals are concealment, disguise, and advertisement. He studied, described and presented examples of such diverse camouflage effects as obliterative shading, disruption, differential blending, high contrast, coincident disruption, concealment of the eye, contour obliteration, shadow elimination, and mimicry. In his wartime lectures at Farnham Castle, he described nine categories of visual deception:
