When asked to describe the energy, flow and transformation through the city, a commercial immediately came to my mind. I've only seen it once, and I don't recall what it was an advertisement for, but it was a powerful image. In the commercial, it showed a city, similar to our own, looks like it may have been New York City, and there were tons of people. The peopled didn't walk though, they were all on individual tracks that they mindlessly flowed across. The ad showed a stop light, sped up, when the walk sign lit up, hundreds of people crossed the street, and then stopped when the don't walk sign lit up, and then the cars passed, and this imagery repeated itself a few more times. Everything was very uniform, all the people appeared to be going to work, but then one person stood out. He wasn't on a track, and he was walking in the opposite direction that everybody else was flowing.
I believe that the point of the commercial was you should find your own track in life. Regardless, the idea of everybody mindlessly following the same routine everyday is a good representation of city flow. While it isn't exciting, it is how a city works, barring of course some unforeseen incident such as a car crash or a natural disaster, at which point the flow is broken down, and to an extent chaos can ensue.
And that I believe is an important thing to take into consideration, if the flow of anything is ever disrupted, things will get confused and pandemonium will take place. Clearly flow is an important part of all of our lives.
The following two scenes are from the first episode of Futurama, in which the main character Fry is frozen in a cryogenic tube for a thousand years, I would have posted the video, but I couldn't find it anywhere:
As you can see, those are two pictures of the same place, but over different time, as the part of the episode went on, it showed 1000 years quickly go by in the background, at which time you saw the city be destroyed by aliens and then rebuilt numerous times, this is a great representation of the transformation of a city over time. Clearly as depicted by the two images above, a city will change tremendously over time (especially if aliens destroy it), man will always build and improve upon the structures that exist (even after being unfrozen from a thousand year slumber), and nothing seems to illustrate this better than this scene in this episode of Futurama. Transformation is a sign of progression and advancements in technology, they gradually happen over time, so we tend not to notice, but if we woke up a thousand years from now, the transformation we would see would probably be too much to handle.