All of the novella's simple but elegant watercolour illustrations, which were integral to the story, were painted by Saint-Exupéry. He had studied architecture as a young adult but nevertheless could not be considered an artist – which he self-mockingly alluded to in the novella's introduction. Several of his illustrations were painted on the wrong side of the delicate onion skin paper that he used, his medium of choice. As with some of his draft manuscripts, he occasionally gave away preliminary sketches to close friends and colleagues; others were even recovered as crumpled balls from the floors in the cockpits he flew. Two or three original "Little Prince" drawings were reported in the collections of New York artist, sculptor and experimental filmmaker Joseph Cornell. One rare original "Little Prince" watercolour would be mysteriously sold at a second-hand book fair in Japan in 1994, and subsequently authenticated in 2007.