Ringworld

I just had an interesting vision. Cities as rings. In the center was an area designated as completely wild and untouchable. Outside of that was parkland that could be visited but not otherwise disturbed. Outside of that were edible forest gardens - miles and miles of them that anyone could care for and partake of. Then outside of that, right at the edge between the garden and the dwellings, were more gardens that needed a little more sun. Then finally, the outer ring was the city, and outside of that, the same sequence in reverse. Each Ring was far enough away from the next one to accommodate the sequence. The city was able to entirely support itself from the inside out, instead of importing from the outside in. It was no longer a parasite, but rather a steward and symbiote. The forest at the center was not owned by anyone. It was its own Being, at the center of which were the Old Trees and they were Left Alone. We were there with its permission, not the other way around...