Frank Stella, Kenneth Noland, Ellsworth Kelly, Barnett Newman, Charles Hinman Ronald Davis, Richard Tuttle, Leo Valledor, Neil Williams, John Levee, David Novros, Robert Mangold, Gary Stephan, Paul Mogenson, Clark Murray, and Al Loving are examples of artists associated with the use of the shaped canvas during the period beginning in the early 1960s. Geometric abstract artists, minimalists, and hard-edge painters may, for example, elect to use the edges of the image to define the shape of the painting rather than accepting the rectangular format. In fact, the use of the shaped canvas is primarily associated with paintings of the 1960s and 1970s that are coolly abstract, formalistic, geometrical, objective, rationalistic, clean-lined, brashly sharp-edged, or minimalist in character. There is a connection here with post-painterly abstraction, which reacts against the abstract expressionists' mysticism, hyper-subjectivity, and emphasis on making the act of painting itself dramatically visible – as well as their solemn acceptance of the flat rectangle as an almost ritual prerequisite for serious painting.