While Joel and Ethan Coen have denied the theory that their characters are all a part of the same universe, they did confirm that four of their films were part of a special trilogy called the Numbskull Trilogy. The four movies are 2000's "O Brother, Where Art Thou?", 2003's "Intolerable Cruelty," 2008's "Burn After Reading," and 2016's "Hail Caesar!"