Free the Solitude Of Prime Numbers (2010) by Paolo Giordano

without much conviction.
    "Yeah," said Denis, in a shrill voice that seemed to have been trapped for too long in his throat. "We sit next to each other."
    Mattia's father nodded seriously and then, his conscience assuaged, he returned to his thoughts. Mattia seemed not even to have noticed that scrap of conversation and didn't take his eyes off the window, through which he was trying to work out whether his perception that the dotted white line in the middle of the road was in fact a continuous line was due merely to his eye's slow response or to some more complicated mechanism.
    Pietro Balossino braked a few feet away from the big gate of the Bai family's property and put on the hand brake as they were on a slight incline.
    "She's pretty well off, your friend," he observed, leaning forward to see over the top of the gate.
    Neither Denis nor Mattia admitted that they barely knew the girl's name.
    "So I'll come back for you at midnight, okay?"
    "Eleven," Mattia replied quickly. "Let's make it eleven."
    "Eleven? But it's already nine o'clock. What are you going to do for only two hours?"
    "Eleven," insisted Mattia.
    Pietro Balossino shook his head and said okay.
    Mattia got out of the car and Denis did likewise, reluctantly. He was worried that Mattia might make new friends at the party, fun, fashionable friends who, in the bat of an eye, would take him away forever. He was worried that he would never get into that car again.
    He politely said good-bye to Mattia's father and, to seem like a grown-up, held out his hand. Pietro Balossino performed a clumsy acrobatic maneuver to shake it without unfastening his seat belt.
    The boys stood stiffly at the gate and waited for the car to turn around before deciding to ring the bell.

    Alice was crouching at one end of the white sofa. A glass of Sprite in her hand, from the corner of her eye she was peeking at Sara Turletti's voluminous thighs, crammed into a pair of dark tights. Squashed onto the sofa they became even bigger, almost twice as broad. Alice thought about the space she occupied compared to her classmate. The idea of being able to become so thin as to be invisible gave her a pleasant pang in the stomach.
    When Mattia and Denis came into the room, she suddenly stiffened her back and looked around desperately for Viola. She noticed that Mattia wasn't wearing a bandage anymore and tried to see if he had a scar on his wrist. She instinctively ran her index finger along the trace of her own scar. She knew how to find it even under her clothes; it was like an earthworm lying against her skin.
    The boys looked around like hunted prey, but in truth not one of the thirty or so kids scattered around the room paid them the least attention. No one except Alice.
    Denis followed Mattia's movements, going where he went and looking where he looked. Mattia walked over to Viola, who was busy telling one of her made-up stories to a group of girls. He didn't even ask himself whether he'd ever seen those girls at school. He stood behind the birthday girl, holding the present stiffly to his chest. Viola turned around when she noticed that her friends had taken their eyes off her irresistible mouth and were looking instead over her shoulder.
    "Ah, you're here," she said rudely.
    "Here," said Mattia, placing the present in her arms. Then he added a mumbled happy birthday.
    He was about to go when Viola shouted in an overexcited voice, "Alice, Alice, come quickly. Your friend's here."
    Denis swallowed the lump in his throat. One of Viola's little friends cackled into another girl's ear.
    Alice got up from the sofa. In the four paces that separated her from the group she tried to mask her syncopated gait, but she was sure that that was what they were all looking at.
    She greeted Denis with a quick smile and then Mattia, bowing her head and saying hi in a faint voice. Mattia said hi back and his eyebrows jerked, making him appear even more spastic in Viola's eyes.
    There followed an uncomfortably long