Purple light passed over the paper, but nothing happened. "Next!" Amy said. She was sure the man in black was going to burst in on them any second. "Whoa!" Dan said. Amy gripped his arm. "You found it?" "No, but look! This whole essay - 'To the Royal Academy.' He wrote a whole essay on farts!" Dan grinned with delight. "He's proposing a scientific study on different fart smells. You're right, Amy. This guy was a genius!
Rick Riordan (2016). “The 39 Clues 1: The 39 Clues: The Maze of Bones”, p.86, Scholastic UK