I suspect that in the same way that people think the most sacred buildings in their culture should be built out of wood or stone depends on their specific culture, rectangular constructions emerge from technological constraints rather than emerging from needs or biological demands.

Take a look at this /r/askscience discussion about human field of vision.[1] Many of the conventions even for rectangular displays are based on metaphors from paper that may not be necessary.

[1] https://www.reddit.com/r/askscience/comments/1va3yj/what_is_...

I didn't even think of watches. I was wondering why an air traffic controller would be surfing the web while working.