I still recall parts of my high school art lesson on Paul Cezanne. Especially the bit where Cezanne was preoccupied with reducing nature to three shapes: the cone, the sphere and the rectangle. I could not see the point of it at the time. Why not paint what was there? Only much later did it dawn on me that Cezanne was doing exactly that. Except Cezanne was able to see past the distractions and details. Everything was in fact a shape falling within those three elements.
It may seem trite today, but not if you want to paint with understanding. To understand that nature and by extension, paintings of nature can be simplified into basic shapes is to unlock the secret to painting nature. Leave the details for the mind to fill in. After all our minds are constantly looking for work.
We must marvel at Cezanne's breakthrough and tenacity to follow this idea. Fortunately he was a stubborn fellow. It took guts to produce paintings like the one above. Imagine this scene in reality. What a mess of details and distractions. What to paint? Cezanne showed us the question remains: What do you leave out? Everything but the shapes!