... you can learn from:
Don't Look Now (1973)
Laura: One of your children has posed a curious question:
if the world is round, why is a frozen lake flat?
John: That's a good question.
Laura: [flipping through book] Ah, here it says
that Lake Ontario curves more than 3 degrees
from its Eastern end to its Western end.
So frozen water really isn't flat.
John: Nothing is what it seems.
Happy 84, Nicolas Roeg!