The wave
When the ship came to the city, the effect was immediately obvious. At first it seemed like an illusion, a mirror image in the ship's shiny shell. But a closer look showed that it was real. The walls of the buildings had bent; the windows had shifted closer together. The city had adapted to the shape of the vessel.
It moved as easily over land as over water, as long as the passages were wide enough. And everywhere it was the same: the houses, churches and office buildings became true to their reflections, but humans and animals did not change. They stared up in wonder and discussed whether or not their own homes would soon be devoid of straight lines. If the effect would wear off when the ship had been gone for a while.
But they never found out, as the ship kept circling within the city borders, eternally following the curves it had created.
