Are geometrical squares found in nature?

Question

We all know that circles and spheres have the greatest surface area, and are found all throughout nature.

Cubes, even, can be found in minerals, etc.

But are naturally occuring squares found anywhere in nature?

Answer 1

The only one i can think of is mudcracks.  When a lake or river bed dries up and the sediment is exposed and that too dries up mud cracks are formed which are sometimes perfect squares