In 1964, a 16-year-old Bruce McAllister wrote to 150 authors asking about the symbolism in their work. A number of authors wrote back, including Ray Bradbury.
The Christmas special brings a new companion and a new interior for the TARDIS. We got the first glimpse of the new interior about a week ago when we saw the top image with the Gallifreyan writing. Now The Doctor himself is showing off the rest of it.