THE DOCTOR: To the rational mind, nothing is inexplicable; only unexplained.
LEELA: So explain to me how this “TARDIS” is larger on the inside than the out?
THE DOCTOR: Hmm? All right, I’ll show you. It’s because insides and outsides are not in the same dimension. [holds up two black cubes of different sizes] Which box is larger?
LEELA: [points to the larger of the two] That one.
THE DOCTOR: Alright. [places the larger cube on the console, walks over next to Leela, holds up the smaller one] Now, which is larger?
LEELA: [scoffs, points at the cube on the console] That one!
THE DOCTOR: But it looks smaller.
LEELA: Well, that’s because it’s further away!
THE DOCTOR: Exactly! If you could keep that exactly that distance away, and have it here, the large one would fit inside the small one.
LEELA: That’s silly.
THE DOCTOR: That’s trans-dimensional engineering: a key Time Lord discovery!
Doctor Who (1963-1989) British science fiction television series, original run (BBC)
14×05 “The Robots of Death,” Part 1 (1977-01-29) [w. Chris Boucher]
(Source)
