I know this sentence is false.

Of course we can find cubic structures in Nature, we can see them, for instance, in mineral's and crystal's structures, as well as in basalt rock structures. Giant's cave in Northern Island, is the best well known example of them.

But what I mean when I say this, is that there are no squares (in the real assumption of the word, the perfect handmade shape called square) in Nature.

What I proved here (and I'm still trying to prove) is that there are no real squares in Nature. In this experiment we just can find rounded forms, circles or spheres and No squares.

A square is an illusion.