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 door handle is the handshake of a building Juhani Pallasmaa, The Eyes of the Skin: Architecture and the Senses What is this static modernism? metaphordoorsinteraction