From a postmodern perspective, graffiti is as legitimate a form of visual expression as any form of fine art; therefore an oil painting is no more valid than graffiti and both are considered art. Graffiti, which is often associated with vandalism and the illicit painting or marking of public spaces, has been part of painting for decades, if not longer. Artists such as Jackson Pollock and Jean Dubuffet, for example, incorporated graffiti-like markings into their work. In 1983, the first exhibition of graffiti art was held at Boymans van Beuningen Museum in Denmark—a sign that graffiti was being accepted as a fine art. The artist Jean-Michel Basquiat (1960—1988) began his career in the late 1970s as a graffiti artist, tagging buildings with short, poetic phrases, along with this friend, Al Diaz. The duo signed their work as SAMO (“same old shit”). In the 1980s, Basquiat developed a neo-expressionist style that incorporated graffiti elements, explored experimental music, and exhibited his work in galleries in New York City and Los Angeles. Another artist, Keith Haring (1958—1990) also began his career by using chalk and Magic Markers to draw his dynamic cartoon images in public spaces, such as New York Metro stations. Both Basquiat and Haring have achieved even greater success since their premature deaths (Basquiat of a heroin overdose and Haring of AIDS), as graffiti art and street art have received increasing mainstream attention.