A category for two-dimensional artworks that include flattened figures or objects, or have shallow depth. Particularly since the 19th century, western artists have rejected hyperrealism and the Renaissance ideal of linear perspective in order to emphasize the illusionistic nature of painting (the flatness of the picture plane), or engage with more conceptual, pre-Modern, or non-western modes of expressing human form. Artists like Edouard Manet and Mary Cassatt, for example, drew inspiration from Japanese ukiyo-e woodblock prints, often rendering broad fields of uniform color that made figures appear compressed against their backgrounds. Clement Greenberg famously identified flatness as the defining characteristic of modern art; the progress towards non-objective abstraction—from Courbet through Mondrian—was, for Greenberg, the predominant story of modernism. Pop Art heightened the emphasis on flatness in the 1960s, a tendency that continues today in much contemporary art.