Cities are about movement. Parmenides and Heraclitus. If Heraclitus is true he must of necessity be untrue.
If you were to conceptualise the movement within a city it would be like the smoke of an atom bomb: a mushroom, with a column of smoke pouring into a centre and then bellowing out in a large spiral
When you read Ann Nortonís attempt to describe population movement in her Shanty towns and scyscrapers the first thing one notices is how immensely complex this movement is.