" What if the blue I see is different than the blue you see?” one of you says in the morning. “The blue is the same, and our eyes are the same. So no way,” says the other of you. Twins in literature are always disguised as each other, or they are sleeping with each other. The banality of “twin sweater sets” cannot make up for Siegmund and Sieglinde. You think that later, of course, much later, when no one wears sweater sets anymore and you have just read a disturbing story by Thomas Mann. “But what if we both call it blue and it’s really a different color but we both have always called it blue so we think we’re seeing the same color but we’re not?” says one of you. “Blue is blue,” the other of you says. “What I see as blue might be what you see as green. We don’t know. You’re not in my eyes. I’m not in your eyes. "

― Cathleen Schine , The Grammarians