^^^ I say:
"Perfect mirror image..."
The mirror does not curve if it's forming a perfect reflection thus, the earth is flat.
At over 4,000 square miles that's some swimming pool.
The surface of the ocean does not curve into a sphere, everybody who has taken their Nikon P900 to the beach knows the earth is flat. The opposite of what you say is demonstrably true; a flat and level surface is "readily observable" across the sea.
/r/unexpectedkoolaidman