"The growth of a city is a cumulative as well as a cyclical process…. Each successive building, railroad line, street-car line, or park leaves a permanent impress upon the character of the city. A pattern begins to form at the very outset that with the lapse of time acquires a certain rigidity. The railroad or park system once laid down holds its position through great changes. The physical character of the city is altered by the imposition of new elements, but the effect of the early direction of its growth and of buildings that have long since vanished is never entirely lost."