 Hugh Cott's 1940 book Adaptive Coloration in Animals introduced ideas such as "maximum disruptive contrast". This uses streaks of boldly contrasting colour, which paradoxically make animals or military vehicles less visible by breaking up their outlines. Cott explains that in ideal conditions, background colour matching together with countershading would "suffice to render an animal absolutely invisible against a plain background", but at once adds that conditions are hardly ever ideal, as they are constantly changing, as is the light. Therefore, Cott argues, camouflage has to break up the perceived continuous surfaces of an object and its outlines. In Cott's own words, "for effective concealment, it is essential that the tell-tale appearance of form should be destroyed." Cott draws an analogy with a pickpocket who carefully distracts your attention, arguing that:
