Ken’s random thought #837:
Gravity alone would have everything made of spheres.
Gravity as negotiator between objects on top of one large object would have everything made of pyramids.
When long, skinner smaller objects are suspended within or by a higher object in an area of lower density than any of them or the large object below, and not touching the large object below, Gravity would make those long skinnier objects into lines that would seem to be perpendicular to the large object below.
However, the perpendicularity of the relationship between the Gravity inspired suspended lines and the large object below is an illusion. There are no right angles.
But to beings also subject to these rules, whose very Brains and the physical processes of sensors into said brains would also follow these rules, they would also prefer these illusions. With these illusions and a desire to make many small objects rest on top of one another without wasting limited materials, …
…. These being would prefer squares and cubes.