Black comedy differs from both blue comedy—which focuses more on crude topics such as nudity, sex, and bodily fluids—and from straightforward obscenity. An archetypal example of black comedy in the form of self-mutilation appears in the English novel Tristram Shandy; Tristram, five years old at the time, starts to urinate out of an open window for lack of a chamber pot. The sash falls and circumcises him; his family reacts with both hysteria and philosophical acceptance.