Human patterns [streets] often follow Nature’s patterns [terrain]. (L) Fort Morgan, Colorado is in the Great Plains and streets run N-S and E-W, oriented to the cardinal directions defined by the spin of the Earth. (C) In central Pennsylvania the Appalachians form long ridgelines and valleys. (R) Cities like State College, PA have street grids aligned parallel to the terrain of the mountains in the area. [Images: Google Maps]