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. If you go on counting, you discover that these pairs gradually become rarer, lost in that silent, measured space made only of ciphers. 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, you come across another pair of twins, clutching each other tightly.

Do you really like studying?" Mattia nodded. "Why?" "It's the only thing I know how to do," he said shortly. He wanted to tell her that he liked studying because you can do it alone, because all the things you study are already dead, cold, and chewed over. He wanted to tell her that the pages of the schoolbooks were all the same temperature, that they left you time to choose, that they never hurt you and you couldn't hurt them either. But he said nothing.

Choices are made in brief seconds and paid for in the time that remains

but his eyes were too dark for her to make out any spark in them

In the end it happens, in some way you couldn't imagine before.

She hadn't chosen him over all the others. The truth was that she hadn't even thought about anyone else.

She found herself thinking of how it would feel to be safely trapped in his arms, with no more possibility to choose.