The development of the clothes dryer followed that of the washing machine. An early design was patented by the African-American inventor G.T. Sampson in 1892. The first successful home drying machines were designed in the 1930s by J. Ross Moore, originally of North Dakota and then of Minneapolis, Minnesota. Moore sold his designs to the Hamilton Manufacturing Company of Two Rivers, Wisconsin, who then called in industrial designer Brooks Stevens to help redesign the machine. It was Stevens who came up with the idea for the window in the dryer's door so consumers would know what the machine was for--Stevens advised Hamilton to display the window-doored dryer in stores with a pair of "boxer shorts flying around in there." Hamilton made the only dryers marketed in the United States before World War II. They were relatively simple machines that operated at fixed temperatures. Modern dryer improvements began in 1960 with Maytag's introduction of electronics. Today's dryers have automatic cycles with varying temperatures and can shut themselves off when the clothes reach the correct stage of dryness. Energy saving dryers have been developed that do not vent to the outside; instead they employ a condensing process that relies on a heat exchanger and a small fan pulling in room air to dry the clothes, thereby avoiding the heat loss associated with a more traditional clothes dryer. Dryers come in varying sizes and colors, and are available to stand independently or stacked with a washer for small spaces.