Pueblo Revival, popular between 1905 and 1940, basically imitates the Native American pueblos of the Southwest. The key distinguishing elements are the projecting roof rafters called vigas. These are generally round or square rafter ends protruding from the wall near the roofline. The roof of the Pueblo Revival structure is usually flat or slightly sloping behind a low parapet. Second and third stories are occasionally stepped or terraced. Round corners, battered walls and straight-headed windows are also characteristic. Most structures are stucco and meant to imitate the adobe walls of the Indian pueblo. Some houses may combine elements of the Spanish Colonial Revival with the Pueblo Revival style.