Pas de deux (2002), in the Flemish Room, is another of the artist's most eccentric works. It consists of two inflatable swans on a round rug, placed inside a stainless steel circle that resembles a pool or a pond. The swans are tied down with strands of wool that seem to grow out of the carpet, one by its beak and the other around the neck, so that the birds appear to be trapped and immobilised. The title of the piece and the presence of the two swansremit to the work of the Russian composer Pyotr Ilyich Tchaikovsky, who the music for one of the world's most famous ballets of all time, Swan Lake, first performed in 1877. Years later, in 1960, the choreographer George Balanchine premiered in New York a short ballet with music that Tchaikovsky had originally written for a third act of Swan Lake, a score that had been lost for a time and was entitled Pas de deux. The Flemish Room contains important pictures from Flanders and Holland, including "The Emperor Charles V and Empress Isabella of Portugal," by Rubens. In this context, "Pas de deux" could refer to the history of Spain and Portugal, which were united during the period from 1580 to 1640. The steel circle is also related to the metal pans we see in "The Old Man and the Maid," a painting by David Teniers the Younger, that also hangs in this room.