A general category for artworks that incorporate comics and cartoons. While today comics are a popular art form incorporating simplified forms, immediacy of line, and humorous exaggeration, often in a narrative series of images accompanied by text, the term originally referred to a preparatory outline drawing for frescoes, tapestries, and stained glass. The development of the modern comic strip of the 18th and 19th centuries is indebted to artists, particularly the social- and political-themed print series of renowned artists such as William Hogarth, Francisco de Goya, and Honoré Daumier. Comic strips began heavily influencing artists in the 1960s. Pop artists like Andy Warhol and Roy Lichtenstein used the style to showcase their interest in "low" or popular imagery, consumerism, and mechanical reproduction techniques, rejecting the artist's hand. Since the 1960s, graffiti and street art have continued to draw upon both the wit and mass appeal of cartoons, as in the politically charged work of Keith Haring.