Let's suppose there are two kinds of geometry — we'll limit it, for the sake of the example. Our kind, Euclidean, and another, which we'll call x. X hasn't much relationship to Euclid. It's based on different theorems. Two and two needn't equal four in it; they could equal y2, or they might not even equal. A baby's mind is not yet conditioned, except by certain questionable factors of heredity and environment.
Rex Holloway - Mimsy Were The Borogoves (1943)