This passage is about Jean Dubuffet, who created a type of art called "rough art."
Do you like to make a mess? The artist Jean Dubuffet sure did. He was interested in art that wasn't made by artists. He liked how children's drawings looked. They didn't know any art rules or methods. They just made whatever they wanted. Dubuffet found this work raw and natural. He started imitating it. He would mess with the paint. Sand would be mixed into it. This made it thick and rough. Or he would mix tar with paint. He applied this with a knife instead of a brush. He even mixed hay with the paint. For a few years he only used white, red, black, and blue. All his paintings had those four colors. Late in life, he made sculptures. These were chunky. They were made of white plastic. He would paint them. Dubuffet's art was called Art Brut. This means "rough art."