The moment the door opened, Jace seized up a yellow pencil lying on the desk and threw it. It sailed through the air and struck the wall just next to Luke's head, where it stuck, vibrating. Luke's eyes widened. Jace smiled faintly. "Sorry, I didn't realize it was you." ... Luke indicated Simon and Clary with a wave of his hand. "I brought some people to see you." Jace's eyes moved to them. They were as black as if they had been painted on. "Unfortunately," he said, "I only had the one pencil." -Jace & Luke, pg.43-