 He goes on to redescribe this relationship in terms of a mathematical theory, put forward by G. Spencer-Brown, having to do with content, image, and reflection, which basically holds that when one moves from a content to an image to a reflection, one reverses the form of the content.This is a complicated idea, but it is also a central trope of the series and is dramatized and redramatized throughout the Nevèrÿon tales in many different forms, perhaps most clearly in the second story in the first volume of tales, “The Tale of Old Venn".Hardly a tale in the cycle of eleven fails to appeal to this concept in some form.