system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do ships have circular windows instead of square ones?
gpt
The joke answer is so that the water doesn't hit you square in the face.

The real answer is that shapes with sharp corners are structurally weak.  Arcs and circles are very strong shapes.  If port holes were squares, the openings would get damaged and worn out sooner.