The painter who experimented with abstract art in Cubism is Pablo Picasso. Picasso, along with Georges Braque, is considered one of the founders of Cubism, an influential art movement that emerged in the early 20th century. While Cubism is known for its fragmented and geometric representation of subjects, Picasso further pushed the boundaries of the style, eventually exploring abstract forms and concepts in his artwork. He developed different phases within Cubism, including Analytical Cubism and Synthetic Cubism, where he deconstructed and reassembled subjects in increasingly abstract ways. Picasso's innovative approach to Cubism played a significant role in shaping modern art and paving the way for further explorations of abstraction.