DOCTOR: Hmm? All right, I'll show you. It's because insides and outsides are not in the same dimension.
(The Doctor gets two boxes from a cupboard.)
DOCTOR: Which box is larger?
LEELA: That one.
(The Doctor places it on the time console then goes over to Leela with the other.)
DOCTOR: Now which one is larger?
LEELA: That one.
DOCTOR: But it looks smaller.
LEELA: Well, that's because it's further away.
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.
DOCTOR: That's transdimensional engineering, a key Time Lord discovery.
