I try to tell them that this kind of intertextual gamesmanship is pretty much how all literature works. There's only one real "author." The rest of us sub-creators simply take what has been given us, rearrange, rewrite, and retell.
There's only one story. Infinite variations, though.
Some of them think this is primarily Penelope's story. But Atwood allows the chorus of maids to subvert and maybe trump Penelope's narrative at every step along the way. In the end, theirs is the final word--at least in this novel.
