 The title book in Charles Yu's "How to Live Safely in a Science Fictional Universe" exists within itself as a stable creation of a closed loop in time.Likewise, in the Will Ferrell comedy "Stranger than Fiction" the main character discovers he is a character in a book that (along with its author) also exists in the same universe.In Douglas Hofstadter's "Gödel, Escher, Bach", there is a narrative between Achilles and the Tortoise (characters borrowed from Lewis Carroll, who in turn borrowed them from Zeno), and within this story they find a book entitled "Provocative Adventures of Achilles and the Tortoise Taking Place in Sundry Spots of the Globe", which they begin to read, the Tortoise taking the part of the Tortoise, and Achilles taking the part of Achilles.