In pursuit of the best method for painting the object in its honest, physical bulk, Paul Cézanne turned to a technique that simplified surface areas of space into compartmentalized sections of color and brushwork. Cézanne painted small cubes of color that distinguished different textural planes of an object's outward surface. Through thickness of paint and changes in the direction of the brushstrokes, he could delineate the subtle alterations of an object's mass. This may sound complex, but in fact the artist was trying to formulate a less complicated way to paint the three-dimensional by narrowing down the focus onto specific qualities of mass, volume, and external surface texture. These ideas later became the foundational inspiration for Cubism; and there they are perhaps more readily explicable. For now we can see examples of what Cézanne is doing in his Mont Saint-Victoire series.
This is just one of a series of paintings the artist made of a mountain in southern France. Cézanne painted it 60 times. With a closer look at the artist's brushwork, we can detect his method for blocks of color. The mountain is painted in chunks, with altering directions of brushstrokes wherever the mountain surface has changed. This is also true of the valley around it. Trees, bushes, and flatland have all been compartmentalized into chunks of color and consistent paintbrush movement. This breaks down (almost mathematically) the three-dimensionality of the scene and therefore better translates it to the flat canvas of the artist. In theory, this was the problem which Cézanne was attempting to solve with his techniques, but it simultaneously lessened the realism of his works. He was more concerned with conveying the ideas behind a certain aspect of the object than in painting realistically an entire scene. This, too, was a form of Impressionism; but the Post-Impressionists took the physicality of Impressionism (its emphasis on the visual world, on sunlight and atmosphere) to new levels.