Outside the window, it's as if an eraser took away the past few centuries of urban development, leaving a sliver of past ecosystems. A rocky ledge nestles between buildings making a quick diagram of different ecosystems: lichen, moss, grass, trees, walls. Sound bounces off the surfaces of the hard brick buildings; activity trickles in from the store on the main street. People and birds sometimes shelter in the alley, put out trash. An exercise class moves through distant windows to a unknown soundtrack.