Adult animation is a genre of animation geared towards adults and sometimes teens. Works in this genre may be considered adult for any number of reasons. They may be noted for using risqué themes, graphic violence, sexuality, or dark humor in a manner that is unsuitable for younger audiences. Works in this genre may explore philosophical, political, or social issues. Some productions are noted for sophisticated and/or experimental storytelling and animation techniques.Before the enforcement of the Hays Code, some cartoon shorts contained humor that was aimed at adult audience members rather than children. Following the introduction of the Motion Picture Association of America film rating system, independent animation producers attempted to establish an alternative to mainstream animation. Initially, few animation studios in the United States attempted to produce animation for adult audiences, but later examples of animation produced for adults would gain mainstream attention and success. The most successful animated features produced in the United States primarily for adult audiences were directed by Ralph Bakshi, including Fritz the Cat, Heavy Traffic and Coonskin.Fox Broadcasting Company has also dedicated an entire evening programming block to adult animation programs, known as "Animation Domination." In Canada, Teletoon offers up its own Teletoon at Night programming block.