Reciprocity Whenever human activities incorporate machines or rigidly prescribed procedures, the modes of human interaction change. In general, technical arrangements reduce or eliminate reciprocity. Reciprocity is some manner of interactive give and take, a genuine communication among interacting parties. Ursula M. Franklin, The Real World of Technology reciprocity
The axis of movement Moving in the city means constantly changing the axis of movement. In general, lateral movement is confined to a single plane, what’s called grade, the ground level. Because circulation in multistory buildings is fundamentally one way—which is to say from the bottom up—the condition at the top is invariably different from that at the bottom. Rooftop circulation is the domain of Fantômas, of cat burglars and fleeing criminals, of lovers, and of those acrobatic enough to negotiate the gaps between buildings. Michael Sorkin, 20 Minutes in Manhattan A Burglar's Guide to the City movement