Paolo Giordano - The Solitude of Prime Numbers

She felt around under the pile of photographs and found a pen. She sat down to write, careful not to smudge the ink with her hand. At last she blew on it to dry it. She looked for an envelope, slipped the photograph inside, and sealed it.

Maybe he'll come, she thought.

A pleasant apprehension gripped her bones and made her smile, as if at that very moment time had begun again.

Before seeking the runway, the plane on which Mattia was traveling crossed the green patch of the hill, passed the basilica, and flew twice over the center of the city in a circular trajectory. Mattia took the bridge, the older one, as his point of reference and from there followed the road to his parents' house. It was still the same color as when he had left it.

He recognized the park nearby, bounded by the two main roads that flowed together into a broad curve bisected by the river. On so clear an afternoon you could see everything from up there: no one could have disappeared into nothingness.

He leaned farther forward, to look at what the plane was leaving behind it. He followed the winding road that climbed part of the way up the hill and found the Della Roccas' building, with its white facade and its windows all attached to one another, like an imposing block of ice. A little farther on there was his old school, with the green fire escapes, their surfaces, he remembered, cold and rough to the touch.

The place where he had spent the first half of his life, the half that was now over, was like an enormous sculpture made of colored cubes and inanimate shapes.

He took a taxi from the airport. His father had insisted on coming to collect him, but he had said no, I'll come on my own, in that tone that his parents knew well and that was pointless to resist.

After the taxi had driven off, he stood on the sidewalk on the other side of the street, looking at his old house. The bag that he carried over his shoulder wasn't very heavy. It contained clean clothes for two or three days at the most.

He found the entrance to the apartment block open and climbed to his floor. He rang the bell and heard no sound from inside. Then his father opened the door and, before they were able to say anything, they smiled at each other, each contemplating the passing of time in the changes that had occurred in the other.

Pietro Balossino was old. It wasn't just the white hair and the thick veins that stood out too much on the backs of his hands. He was old in the way he stood in front of his son, his whole body trembling almost imperceptibly, and leaned on the door handle, as if his legs were no longer enough on their own.

They hugged, rather awkwardly. Mattia's bag rolled off his shoulder and slipped between them. He let it fall to the floor. Their bodies were still the same temperature. Pietro Balossino touched his son's hair and remembered too many things. Feeling them all at the same time gave him a pain in his chest.

Mattia looked at his father to ask where's Mum? and he understood.

"Your mother's resting," he said. "She didn't feel very well. It must be the heat these past few days."

Mattia nodded.

"Are you hungry?"

"No. I'd just like a little water."

"I'll go and get you some."

His father quickly disappeared into the kitchen, as if looking for an excuse to get away. Mattia thought that that was all that was left, that parental affection resolves itself into small solicitudes, the concerns his parents listed on the telephone every Wednesday: food, heat and cold, tiredness, sometimes money. Everything else lay as if submerged at unreachable depths, in a mass of subjects never addressed, excuses to be made and received and memories to be corrected, which would remain unchanged.

He walked down the corridor to his bedroom. He was sure he would find everything as he had left it, as if that space was immune to the erosion of time, as if all the years of his absence constituted only a parenthesis in that place. He felt an alienating sense of disappointment when he saw that everything was different, like the horrible feeling of ceasing to exist. The walls that had once been pale blue had been covered with cream-colored wallpaper, which made the room look brighter. Where his bed had been was the sofa that had been in the sitting room for years. His desk was still at the window, but on it there was no longer anything of his, just a pile of newspapers and a sewing machine. There were no photographs, of him or of Michela.

He stood in the doorway as if he needed permission to enter. His father came over with the glass of water and seemed to read his thoughts.

"Your mother wanted to learn to sew," he said, as if by way of justification. "But she soon got fed up with it."

Mattia drank the water down in one gulp. He rested his bag against the wall, where it wasn't in the way.

"I have to go now," he said.

"Already? But you've only just got here."

"There's someone I have to see."

He walked past his father, avoiding his eyes and sliding his back against the wall. Their bodies were too similar and bulky and adult to be so close to each other. He took the glass through to the kitchen, rinsed it, and set it upside down on the draining board.

"I'll be back this evening," he said.

He nodded good-bye to his father, who was standing in the middle of the living room, at the same spot where in another life he was hugging his mother, talking about him. It wasn't true that Alice was waiting for him, he didn't even know where to find her, but he had to get out of there as quickly as possible.

They wrote to each other during the first year. As with everything else that concerned them, it was Alice who had started it. She had sent him a photograph of a cake with a rather clumsy Happy Birthday written with strawberries cut in half. She had signed the back only with an A -and nothing more. She had made the cake for Mattia's birthday, and then had thrown the whole thing into the trash. Mattia had replied in a letter of four closely written pages, in which he told her how hard it was to start over in a new place without knowing the language, and in which he apologized for leaving. Or at least that was how it seemed to Alice. He hadn't asked her anything about Fabio, either in that letter or in the ones that followed, and she hadn't talked about him. Both of them were aware, however, of his strange and menacing presence, just beyond the edge of the page. Partly for that reason they soon began to reply to each other's letters coldly and at increasingly longer intervals, until their correspondence faded away entirely.

A few years later Mattia had received another card. It was an invitation to Alice and Fabio's wedding. He had stuck it on the fridge with a piece of tape, as if, hanging there, it would inevitably remind him of something. Each morning and each evening he found himself standing in front of it and each time it seemed to hurt him a little less. A week before the ceremony he had managed to send a telegram that said Thank you for invitation must decline due to professional obligations. Congratulations, Mattia Balossino. In a shop in the city center he had spent a whole morning choosing a crystal vase that he had sent to the couple at their new address.

It was not to this address that he went when he left his parents' house. Instead he headed for the hill, to the Della Roccas', where he and Alice had spent their afternoons together. He was sure he wouldn't find her there, but he wanted to pretend that nothing had changed.

He hesitated for a long time before pressing the buzzer. A woman replied, probably Soledad.

"Who is it?"

"I'm looking for Alice," he said.

"Alice doesn't live here anymore."