Drag in any direction, for as long as you like. Every chunk ahead is minted from the seed and its own coordinates; every chunk behind is thrown away.
chunk = f(seed, chunkX, chunkY)
Nothing pinned. Mark the chunk under the middle of the frame, travel until it is evicted, then come back to it.
Pinned and fingerprinted. Keep travelling until it leaves memory.
Evicted — it is not in memory anywhere. Go back to it and it will be re-minted from the seed.
Evicted, re-minted on return, and bit-identical. Same seed, same world.
It came back DIFFERENT. That is the one bug this exhibit exists to catch.