“In 1936, in Paris, I visited an exhibition of so-called abstract painting in the company of the late Maurice Heine, the erudite specialist on the Marquis de Sade, and he noticed that during the whole visit my eyes kept coming back to a corner of the exposition room in which no work was being exhibited. “You seem to be systematically avoiding looking at the paintings,” Heine said to me, “It's as though you were obsessed by something invisible!” “It's nothing invisible,” I replied to reassurehim, “I just can't help looking at that door—it is so well painted. It is by far the best painted thing in the whole exposition."