You and your twin sister are both staying on campus over the summer to take biochem. It's the day before the final, and you just went over to her dorm room to study together. You're quizzing each other on metabolic pathways, teasing you about how she's the smarter twin, when she asks to look up something in your textbook. A loose page of notes falls out of the binding. Scrawled on the bottom are the words "I'm in love with my twin sister."