One reason I love street photography is that it has so many levels. Down at the tinniest scale, you can get some flopping and twisting. Higher up, there is some immense crawling, feeding and sometimes dividing. The street seems to be organized like any animal system or like a big organism, which must obey its own rules in order to survive.
For some may be, a day is a lifetime. Others must weather centuries. When millions of humans get together, they form ecosystems that wax and wane in ways that could not be predicted before. And over the course of generations, cities, quarters and streets take on a own personality, no longer passive bits of unreadable code, but units of selection that can sweep across a city, which give birth to ideas and trends that leap from species to species.
Sometimes it starts with on species going its way in life up and down on different stairs and levels.