Tiles have been used in most countries of the world as a sturdy building material for floors, roofs, fireplace surrounds, and surface toppings. The cuerda seca (dry cord) technique of decoration uses a greasy pigment to separate different glaze colors during firing. In cuenca (raised line) decorated tiles, the design is impressed, leaving ridges that separate the glaze colors. Dust-pressed tiles, tiles made by finely ground raw materials shaped in molds at high pressure before firing, were made by the J.B. Owens Floor & Wall Tile Company and other U.S. companies. Many of the American tiles are listed under the factory name.