Anne Truitt (March 16, 1921-December 23, 2004) was an American artist known for her large-scale Minimalist sculptures.
Biography on Wikipedia: https://en.wikipedia.org/wiki/Anne_Truitt

Morning Choice by Anne Truitt
1968 / Acrylic on marine mahogany plywood / 72″x14″x14″ / Saint Louis Art Museum, Missouri

Anne Truitt on Artnet: http://www.artnet.com/artists/anne-truitt/

Further reading:
https://nmwa.org/art/artists/anne-truitt/
https://www.nga.gov/exhibitions/2017/in-the-tower-anne-truitt.html
https://www.smithsonianmag.com/arts-culture/anne-truitts-artistic-journey-143259617/