Roy Lichtenstein was an American pop artist known for his paintings that incorporated cartoon images. One of the first subjects he painted after his breakthrough in pop art was landscapes. The document discusses key elements of landscape art including depicting the relative sizes of objects based on their distance, the use of overlapping shapes, varying colors and clarity based on an object's position in the foreground, middleground or background, the inclusion of a horizon line, and how Lichtenstein found inspiration for his landscapes from cartoon backgrounds rather than nature itself.