Le narrateur a un frère siamois. Il raconte ses réflexions d'enfant à la vue d'un petit garçon sans double.
He [a child of seven or eight] cast a short blue shadow of the ground, and so did I, but in addition to that sketchy, and flat, and unstable companion which he and I owed to the sun and wich vanished in dull weather, I possessed yet another shadow, a palpable reflection of my corporal self, that I always had by me, at my left side, whereas my visitor had somehow manage to lose his, or had unhooked it and left it at home.

Vladimir Nabokov, "Scenes from the life of a Double Monster", in Nabokov's Dozen