Since the down of the agriculture and the human civilization itself ten thousand years ago people are tend to constrain and contain the nature, put it into the strictly-defined limits. This is how we are transforming our area of habitat, this is what defines us as a specie.
The nature says nothing against it. It is silent. It uses all the space available for growth and proliferation. If we draw it in squares, nature will shape itself in squares even though there are no perfect squares and cubes in the wild. Nature will fit the ever changing environment not matter if it is changing due to cosmic reasons or by the will of the people.
Here are some good illustrations for this. In urban environment trees are shaping their root system to replicate the man-made patterns: squares, cubes, octagons…