Why Don't Birds Lay Square Eggs?

What is ”egg-shaped” even? I used to think it was the shape of a chicken egg. Then one day I saw a collection of eggs from lots of different bird species, and I realized just how many different kind of egg shapes there really are! I had to know why. And it turns out a couple teams of scientists had wondered the same thing. Here’s what science says about why eggs are egg-shaped, if that's even a thing, which I’ve learned it might not be. Evolution of bird eggs, go!