José Clemente Orozco had labored five months on his new muraland never laid a brush on it. The owlish Mexican master spent his evenings hunched in a kitchen chair in his studio, under a single powerful lamp, drawing pictures. Mornings he would go out to the brand-new government normal school to work, by remote control, on the painting itself.
The mural, on a concave wall in the school's open-air theater, covered a thousand square feet. Standing on the stage in front of it and flailing his arms like an orchestra conductor, Orozco "painted" by means of shouted instructions to half a dozen...