They built a freeway through the city.
Then, they built a loop around the city so people could bypass the city.
Then, they built another loop around the loop so people could bypass the city and the inner loop around the city.
Over time, they built more and more loops.
Until they ran into another city’s loop around a loop around a loop.
The two cities thought about starting a war.
Instead, they kept building loops, trying to loop around the other city.
In the long-distant future, the people were gone.
So were the cities.
But the many loops remained.