I have a theory that the rabbit hole down which the estimable Mr. Dodgson had young Alice fall was, in fact, a rabbit Klein surface*. And I'm not talking about one of those 3-dimensional wannabe Klein bottles one can buy on the Interweb, but the real deal which only exists in four dimensions.

I have evidence to support this theory in the form of previously unpublished pen-and-ink drawings, originally produced as illustrations for Alice's Adventures in Wonderland. Said draings prominently feature a creature which seems to be a cross between a dog and a duck.

* The Klein bottle was originally called the Klein surface. It was mislabeled due to confusion between the German words for "surface" (Fläche) and "bottle" (Flasche).