The context in which Marc worked suggests that he used these correspondences programmatically, Marc wrote: "Each color must clearly say 'who and what it is , and must, moreover, be related to a clear form." During his career, Franz Marc created approximately 60 pieces in lithography and woodcut. Many of his pieces depicted animals, in their natural environment and habitats. The use of bright, vivid colors was also often seen in his works. Color was extremely important to Marc. He not only understood the potential of color to influence mood, but he developed a specific theory about color symbolism. His color analysis associated blue with masculine, yellow with feminine and red with the often violent physique. He adopted a cubist approach, in the display and creation of the animals he depicted in his works; simplicity was also often seen as a means to his creative process, as most pieces simply focused on the animal and raw emotion, instead of drawing from external factors, to create the artworks printed during the his work.