Circles circles all around

I was driving through Gig Harbor a few days ago, and the new commercial district is bereft of traffic lights, instead, the area is a series of traffic circles connected by short roads. As I was putting along through this labyrinth of circles and lines, my mind began to wander, to wonder...

And so these thoughts lead to an abstract notion of an intersection, and then a tiered circular intersection, and from that, I envisioned circular intersections tiered and connected in a larger circle, with tiered circles beyond, rising upward. Then it seemed that the circles rising from a central depression was a poor design for a city, and I inverted the concept, making them rise to a pinnacle and decending in tiers lower and lower. At this point, my mulling notion of subterranean cities in spherical voids connected with the initial thought of the tiers rising from a depression, and I realized I had a solid concept for one (or more) of the cities in this fictional world I am envisioning.

So now, I have a new layout for a reasonably artistic and unique set of cities in spheres. This will certainly not be the only design style for these places, but it will definitely be the signature for a particular class of such cities, in much the same way that many periods of history have seen the development of unique layouts or styles.