" Valdrada’s inhabitants know that each of their actions is, at once, that action and its mirror-image, which possesses the special dignity of images, and this awareness prevents them from succumbing for a single moment to chance and forgetfulness. Even when lovers twist their naked bodies, skin against skin, seeking the position that will give one the most pleasure in the other, even when murderers plunge the knife into the black veins of the neck and more clotted blood pours out the more they press the blade that slips between the tendons, it is not so much their copulating or murdering that matters as the copulating and murdering of the images, limpid and cold in the mirror.

At times the mirror increases a thing’s value, at times denies it. Not everything that seems valuable above the mirror maintains its force when mirrored. The twin cities are not equal, because nothing that exists or happens in Valdrada is symmetrical: every face and gesture is answered, from the mirror, by a face and gesture inverted, point by point. The two Valdradas live for each other, their eyes interlocked; but there is no love between them. "

― Italo Calvino , Invisible Cities