In modern stamp manufacture, the gummed surface of the paper is broken up into minute sections by being drawn across steel blades set diagonally in various types of machines. The tiny divisions between the gum particles allow for expansion and contraction in varying temperatures, and counteract any tendency to curl. This non-curling gummed paper rarely shows the action of the breakers in British and colonial stamps; but other types of breakers as used in Germany and U.S.A. show a colourless pattern, described in Germany as riffled (riffelgummierung).