The American painter, Brice Marden, was a friend of Mapplethorpe and Patti Smith. His austere, monochrome abstractions were being widely shown by the mid 1970s and he had a solo exhibition at the Guggenheim Museum in New York in 1975. Almost in emulation of Marden’s carefully balanced compositions, Mapplethorpe has divided his image into two, almost equal, halves by a vertical pipe on the wall. The triangular shape formed by the seated Marden on the left is counterbalanced by a group of stacked paintings on the far right. [http://www.tate.org.uk/art/artworks/mapplethorpe-brice-marden-ar00147]