The pen-and-ink pointillist work of Rex portrays the darker, rougher side of gay sex. Accordingly, he was commissioned to create ads and imagery for backroom clubs, leather bars and sex boutiques, including the Mineshaft, the Pleasure Chest and the Saint. In addition to illustrations for newsstand porn, his work (some of it outside the restrictions of the mainstream publishers) can be seen in self-published folios and several books. He was a pioneer in offering his work as “art” prints, and his worked influenced the photographer Robert Mapplethorpe.