The other wonderful thing about myth and folktale elements is that nearly every story is in segments, which can be taken apart and either recombined or included on their own. In this form they carry the same weight but their meaning often alters. I first grasped this at the age of about eleven, when I was allowed to read a scholarly book…which was mostly sixteen versions of the same Persian folktale–the one where the younger prince fetches the princess from the glass mountain–placed in such an order that, as the details of the story altered, you watched it changing from one sort of narrative (the trial of strength and valour) to another (the test of character), while the outline of the story itself never changed. This kind of thing fascinates me. When I was a student I imagine I caused Tolkien much grief by turning up to hear him lecture week after week, while he was trying to wrap his series up after a fortnight and get on with The Lord of the Rings (you could do that in those days, if you lacked an audience, and still get paid). I sat there obdurately despite all his mumbling and talking with his face pressed up to the blackboard, forcing him to go on expounding every week how you could start with a simple quest-narrative and, by gradually twitching elements as it went along, arrive at the complex and entirely different story of Chaucer’s Pardoner’s Tale–a story that still contains the excitement of the quest-narrative that seeded it. What little I heard of all this was wholly fascinating.
— Diana Wynne Jones