When did Warhol first show his work ?
In fact , Castelli had visited Warhol 's gallery in 1961 and said that the work he saw there was too similar to Lichtenstein 's , although Warhol 's and Lichtenstein 's comic artwork differed in subject and techniques ( e.g. , Warhol 's comic - strip figures were humorous pop culture caricatures such as Popeye , while Lichtenstein 's were generally of stereotypical hero and heroines , inspired by comic strips devoted to adventure and romance ) .