Two Mirrors
Two Mirrors
[Megan sets up a full mirror facing a bathroom-counter mirror.]
[Megan looks through the bathroom counter mirror to see the infinite reflections.]
Megan: Bloody Mary, Bloody Mary, Bloody Mary.
[Megan ducks as the infinite Bloody Marys pop out between the two mirrors above her head.] RAAGHHHHH
In the right-most panel, Megan can still be seen standing in the right mirror even though she had ducked down at that point.

In folklore, Bloody Mary is a legendary ghost or spirit conjured to reveal the future. She is said to appear in a mirror when her name is called multiple times (mainly 3). The Bloody Mary apparition may be benign or malevolent, depending on historic variations of the legend. The Bloody Mary appearances are mostly "witnessed" in teenage group participation games, often as part of a game of truth or dare. This is Bloody Mary's first appearance in xkcd, the second being 2364: Parity Conservation .
In this comic, Megan sets up two mirrors facing each other, in which reflections bounce back and forth between the mirrors until the mirrors absorb all the light. She then says "Bloody Mary" three times (as in the folklore) before ducking, conjuring an infinite number of spirits who jump from the mirror towards each other. It's not clear if they simply collide, or pass into the opposing mirror. Megan may be attempting an experiment either in particle physics upon colliding mirror matter or bridging Mirror Universes by enabling Bloody Mary’s opposing characterizations to interact with each other, or both.
Douglas Hofstadter (also referenced in 917: Hofstadter ) is the author of Gödel, Escher, Bach and I Am a Strange Loop . In the former book, among many other discussions of infinite loops, he points a television camera at the screen on which its image is projected, forming an endless series of screens similar to panel 2 of this comic. In the latter book he focuses on the idea of minds being self-referential. "In the end, we are self-perceiving, self-inventing, locked-in mirages that are little miracles of self-reference". This blends with the idea of the images of the person looking in the mirror being reflected endlessly.
[Megan sets up a full mirror facing a bathroom-counter mirror.]
[Megan looks through the bathroom counter mirror to see the infinite reflections.]
Megan: Bloody Mary, Bloody Mary, Bloody Mary.
[Megan ducks as the infinite Bloody Marys pop out between the two mirrors above her head.] RAAGHHHHH
In the right-most panel, Megan can still be seen standing in the right mirror even though she had ducked down at that point.
