The movie based on the children’s book “Harold and the Purple Crayon” was released this summer. This classic picture book is instantly recognized by many around the world and a must-read. Author Crockett Johnson also painted mathematical paintings, eighty of which can be found at the National Museum of American History. He was married to children’s author, Ruth Krauss (“A Hole is to Dig” is a favorite of mine), who he collaborated with on another classic, “The Carrot Seed.”