Ganado emerged as one of the original style centers during the Rug Period 1890-1920, and is often thought of as the classic Navajo rug. An uncomplicated geometric design theme dominated by the serrate, or stair-stepped diamond, on a beautifully dark red background, characterizes the Ganado. Ganado rug colors are traditionally red, black, gray and white, usually with a border of black or red, and sometimes an additional inner border. In some pieces one diamond is drawn out from end to end; in others, three adjoining or interlocking diamonds fill most of the space. Remaining areas may be filled with crosses, frets, triangles or zigzags.