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.

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

They lived the slow and invisible interpenetration of their universes, like two stars gravitating around a common axis, in ever tighter orbits, whose clear destiny is to coalesce at some point in space and time.

In fact, they didn't talk much at all, but they spent time together, each in his own abyss, held safe and tight by the other's silence.

Even though he was afraid to admit it, when he was with her it seemed it was worth doing all those normal things that normal people do.

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

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