Complex sentence: Richard Alden Griffin (June 18,1944-August 18,1991) was an American artist and one of the leading designers of psychedelic posters in the 1960s, as well as a contributor to the underground comix movement whose work appeared regulaly in Zap Comix.
Split into simpler sentences: Richard Alden Griffin (June 18,1944-August 18,1991) was an American artist and one of the leading designers of psychedelic posters in the 1960s. He was also a contributor to the underground comix movement whose work appeared regulaly in Zap Comix.