Picasso, Harlequin, 1915. Oil on Canvas, 183.5x105cm. Museum of Modern Art, New York.

Matisse, Interior with Goldfish, 1914. Oil on Canvas. 146.5x112.4cm. Museum of Modern Art, New York

These two paintings by Matisse and Picasso, are self referential (Richardson, 1996, pp. 387). The semi-primed canvas held by the harlequin by Picasso shows a sillouette of the artists profile. With the Matisse, there exists a rough sketch for the Interior which shows an artist (Matisse himself) in the top right hand corner of the composition. This artist has been all but painted out in the finished painting; all that remains is a palette with a mysterious thumb sticking through, "a feature borrowed from Cezanne", the rest is a semi-cubist abstraction. Richardson sees this as a 'cryptic passage' within the work - a coded nod to Picasso and the cubism that Matisse once denounced, but which he admitted "spurred him on to some of his finest moments".

Cezanne, Self-Portrait with Palette, 1885-87. Oil on Canvas, 92x73cm. Buhrle Foundation, Zurich.