“Mattia thought there was nothing good about having his mind. That he would happily have unscrewed it and replaced it with a different one, or even with a package of biscotti, provided it was empty and light. He opened his mouth to reply that feeling special is the worst kind of cage that a person can build for himself, but he didn't say anything.”

“Mattia's voice no longer stirred anything in his stomach, but he was aware of the idea of him and always would be, as the only true benchmark for everything that had come afterward.”

“All Mattia saw was a shadow moving toward him. He instinctively closed his eyes and then felt Alice’s hot mouth on his, her tears on his cheek, or maybe they weren’t hers, and finally her hands, so light, holding his head still and catching all his thoughts and imprisoning them there, in the space that no longer existed between them.”

“Mattia stayed right where he was, feeling those clothes that weren't his, but with the pleasant sensation of disappearing into them.”

“For Alice and Mattia, the high school years were an open wound that had seemed so deep that it could never heal. They had passed through them without breathing, he rejecting the world and she feeling rejected by it, and eventually they had noticed that it didn't make all that much difference. They had formed a defective and asymmetrical friendship, made up of long absences and much silence, a clean and empty space where both could come back to breathe when the walls of their school became too close for them to ignore the feeling of suffocation.”

“Prime numbers are divisible only by 1 and by themselves. They hold their place in the infinite series of natural numbers, squashed, like all numbers, between two others, but one step further than the rest. They are suspicious, solitary numbers, which is why Mattia thought they were wonderful. Sometimes he thought that they had ended up in that sequence by mistake, that they'd been trapped, like pearls strung on a necklace. Other times he suspected that they too would have preferred to be like all the others, just ordinary numbers, but for some reason they couldn't do it. This second thought struck him mostly at night, in the chaotic interweaving of images that comes before sleep, when the mind is too weak to tell itself lies.In his first year at university, Mattia had learned that, among prime numbers, there are some that are even more special. Mathematicians call them twin primes: pairs of prime numbers that are close to each other, almost neighbors, but between them there is always an even number that prevents them from truly touching. Numbers like 11 and 13, like 17 and 19, 41 and 43. If you have the patience to go on counting, you discover that these pairs gradually become rarer. You encounter increasingly isolated primes, lost in that silent, measured space made only of ciphers, and you develop a distressing presentiment that the pairs encountered up until that point were accidental, that solitude is the true destiny. Then, just when you're about to surrender, when you no longer have the desire to go on counting, you come across another pair of twins, clutching each other tightly. There is a common conviction among mathematicians that however far you go, there will always be another two, even if no one can say where exactly, until they are discovered.”

“Mattia thought that he and Alice were like that, twin primes, alone and lost, close but not close enough to really touch each other.”