Warning signals are honest indications of noxious prey, because conspicuousness evolves in tandem with noxiousness. Skinner notes that credit is typically a function of the conspicuousness of control. The conspicuousness of veins depends on a number of features. The lighthouse, compound walls and adjacent buildings are painted white for daytime conspicuousness. However, the conspicuousness of the focal point depends on time, place and people themselves. Conspicuousness can also be reduced by siting masts near, or on, other structures.