Created in 1939 by Homer Hoyt, this model was yet another to explain urban structure. Unlike it's predecessor, Hoyt stated that a city develops in a series of sectors, not rings. Certain areas of a city are more attractive because of various activities and environments. When a city grows, its activities and sectors expand in a wedge. When a district with high-class housing is established, more expensive housing is then built on the outer edge of that sector. Thus the better housing is located in a corridor extending from the outer edge of the city.