 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.