Both were born 24 days apart in the same year. Liliana was born first. Their parents were always friends, and therefore they both knew each other all their lives. Liliana always had it easy for dealing with people and to put a smile that spread joy to everyone, but also a terrible memory and attention for books. Arturo, on the other hand, always had a sharp mind, incredibly curious and healthily skeptical, although he was always quiet, introverted and somewhat shy. Both children learned to depend on each other even before they said their first words, for better or worse.

----------------------------

When they were six years old, they once went with their first grade class to the park next to the school. The teachers gave them various activities as part of the outing: playing hide-and-seek, running races, looking for flowers, things like that. Liliana, always comfortable around other people, took the leadership of the whole class effortlessly and commanded her peers to do the activities in the way and order she liked. All the children wanted some of her attention and she gave it to them as best she could; some wanted her to see the flower they had found, others wanted to skip the activities and climb trees, another wanted to dig a hole with her.

Finally it was time for a break. The teachers gave everyone their snack and told them they had fifteen minutes to eat. Immediately the entire class surrounded Liliana, each child asking to eat with them or with their group to talk. However, she realized that it had been a long time without Arturo. She quickly looked for him with her eyes and found him eating alone under a tree. Liliana then ignored the rest and went to sit next to him. He looked at her, smiled and opened the package with his snack. Liliana did the same. They both ate together. Later, when recess was over and the teachers told them to pair up, Liliana and Arturo held hands before anyone else. Several of Liliana's friends went to ask her to pair up with them anyway, but Liliana turned them all down.

----------------------------

A little later, when they were doing one of the activities indicated by the teachers, Liliana fell while running. Arturo immediately went to help her. Liliana pouted, ready to burst into tears. Arturo examined her hands and knees and wiped them with saliva.

—Did it hurt?— he asked.

Liliana nodded.

—You don't have anything— said the boy— think about it, did it really hurt?

Liliana held back her tears. Arturo kept silent while she thought about it. Finally the girl shook her head. Arturo smiled and helped her up.

—How did you know it didn't hurt?— she pleaded.

—Because I know you're scared of falling and you fall on something hard— he explained in his six—year-old voice— you were just scared.

Liliana wiped her watery eyes and smiled.

—Well, let's go.

She quickly turned to continue running, but Arturo grabbed her hand to stop her.

—What?— she pleaded.

—Your shoelace came untied— Arturo told her— if you keep running, you'll only fall again.

Liliana looked at her shoes. Just as Arturo had said, one of her shoelaces was untied. Unfortunately, she didn't know how to tie it. Then she looked at Arturo's slippers, perfectly knotted.

—Do you know how to do it yourself?— she asked him.

—Yes— he answered.

—Can you do it for me? I don't know.

Arturo looked at her slippers.

—I'd better teach you.

Liliana frowned. It was easy for her to manipulate people into doing the tasks she didn't like, but Arturo always resisted and tried to teach her. He was obnoxious.

—But if you know how to do it, why don't you just do it?— she argued.

—Because I don't want to do it all the time.

Liliana grabbed her skirt with both hands and swayed from side to side in frustration. That used to work with big kids and adults. Arturo sighed, bent down at her feet and unbuckled the laces of her other slipper. Now Liliana had both slippers unbuckled.

—What are you doing!— she pleaded.

—Showing you. Take a good look.

Liliana had to accept that she could not force Arturo to do what she wanted. Then she realized that he used to be like that; he was always there for her, but in ways different from the rest of the world. She watched as Arturo explained how to tie her slippers. Resigned, she bent down and tried to do the same with the other foot, but the laces didn't form the knot, they just fell untied.

—What's going on?!— she exclaimed.

—You're skipping a step— said Arturo.

He showed her again, step by step to make her understand. Liliana tried a second, third and sixth time, but she didn't succeed. She began to pout in frustration.

—I'm no good at this!— she finally exclaimed— I'm stupid, that's it!

—No, Lili, you're not stupid— Arturo assured her.

He wanted to show her how to do it again, but Liliana pulled her hands away from her laces in a huff and sat down, folding her arms. Arturo realized her anger. He had never been good at dealing with people, but he was an expert on Liliana and knew exactly what he should do.

—What happened in the last episode of the Flower Princess?

Liliana was puzzled by the question.

—What? But we watched it together— Liliana reminded him.

—But your annoying sister bothered me half the episode and I never knew where the fish man appeared from.

—What?

Liliana proceeded to explain to him the entire episode of the animated series they watched together. A few minutes later, Arturo understood. Liliana sighed and stood up.

—Shall we go? We have to finish the activity.

—Before that, you have to tie your shoelaces— the boy reminded her.

Liliana looked at her feet again, with displeasure.

—All right, let's try it again.

—We'll go step by step this time— said Arturo.

Slower than all the previous times, Liliana imitated Arturo's movements one by one, until he released the tied laces. Liliana did the same and, to her surprise, the laces on her foot were also tied. She could not contain her surprise.

—It can't be!— she exclaimed, dumbfounded— How did you do it?

—I told you you could do it, Liliana— said the boy.

Liliana hugged him. Then they stood up and continued with their activity.

***

As they grew older, their personalities only became more distant and their relationship closer. Arturo read almost all the material available for mathematics, physics, chemistry and astronomy, and began to search for the most recent scientific discoveries with attention. He stopped studying for his school's science classes, since everything his professors said was basic stuff to him. The only class he didn't do well in was physical education. Even so, he was the quietest and most antisocial boy in the whole school. He almost never initiated conversation with others, but always accepted when others asked him to explain something they had not understood in class. Everyone started asking him for explanations before a test, but no one was interested in him once they were done. However, he didn't mind; he liked to deliver knowledge even if there was no prize at the end. Liliana, noticing that he had almost no friends besides her, forced him many times to look for people: she assigned him to extracurricular activities and made sure he shared with others even a little bit. Arturo never complained, he understood that Liliana was doing it for his own good, he also understood the benefits of the biological process that his body activated when he socialized with people his age, because he had studied it.

For her part, Liliana went from being the leader of her class to a kind of celebrity within the school. From the older grades to the younger ones, boys and girls, everyone knew her and loved her. She was every teacher's favorite student, no matter how much they denied it. She received the best friend award each of the twelve years she spent at the school. In the neighborhood people greeted her, even from other schools people would show up who wanted to hang out with her. The reason everyone liked her so much was because she was simply friendly, knew how to handle herself and knew how to present herself as an interesting girl. In everyone's eyes she appeared as a kind of "super girl", capable of transforming a simple conversation into a momentous and exciting event. Even so, she was doing very poorly in her studies. Arturo helped her, the teachers tried to explain everything to her, but Liliana had a horrible lack of concentration when she was put in silence in front of a test. Boring things like mathematical laws or elements of the periodic table would go in one ear and out the other.

----------------------------

As she grew older, Liliana's circle of friends expanded by leaps, while Arturo's barely changed. In sixth grade Liliana found herself surrounded at every moment by others outside her home, people who used her time and took the time she shared with Arturo.

For his part, the boy began to focus on his extracurricular studies and the latest discoveries in the scientific world. He began to spend his time in libraries and in his room, reading day and night.

However, as the months passed both Liliana and Arturo gradually became more and more distressed, to the point of being miserable all day long not knowing why. Liliana lost interest in her friends and Arturo in science. Their world became monotonous.

In that state, Liliana realized that while many people cared about her, none offered her the degree of intimacy and comfort she needed. Even her older sister, with whom she shared almost everything, Liliana had to make a little effort to mold herself to her: listening to her badmouthing her parents, keeping her cigarettes secret, adjusting to the boyfriend of the week she brought home, things like that.

Arturo found himself more alone than ever. Without Liliana to push him to see others, he had no incentive. He knew his body needed to share with others more than it was doing, but making that effort was a huge tedium, staying in to read and learn was much more appealing even though he knew the consequences.

Finally, Liliana's parents took them both for a ride in the mountains. The trip was relaxing. Liliana neither liked nor disliked the mountains, but she liked to travel to places with beautiful views, to breathe fresh air, that sort of thing. For Arturo it was a waste of time, but he was only 12 years old and adults were in charge of his time.

They parked in a park in the foothills, got ready and started up one of the easier trails. Both of Liliana's parents were happy, but engrossed in each other. The children walked next to one another out of habit. They didn't talk much at first, concentrating on the path and the scenery at the same time, but soon they began to get used to it. Then they looked at each other and realized something neither had expected: the other had changed. It had barely been a detail they couldn't name, but they both realized that something had changed in their faces.

—How long had it been since we had been together?— Liliana asked.

Arturo thought about answering with "we see each other every day at school", but he knew Liliana meant actually hanging out.

—A long time— he said at last.

They were both silent, not knowing what else to say. They immediately began to reflect on their situation. Meditating, they continued along the path for a long time in silence.

Liliana began to think about the difference between Arturo and the rest of the people. Almost everyone wanted to talk to her because she was nice and a good conversation partner, everyone constantly tried to pamper her to win her approval: mostly they gave her gifts or did her favors. Arturo was one of the few who expected things from her, who did not treat her as a saint, but as an equal, someone he could shamelessly lean on when he had problems he could not solve on his own, and someone that would pick her up without question when he saw her falling. Liliana did not have that trust with her sister or with her best friends.

Arturo, in the meantime, had fewer people in his life with whom to compare Liliana, but he noticed that his emotional state improved enormously just by spending some time with her; talking, looking at her, knowing that someone willing to pay attention to him was at his fingertips. There was something very strange about that, magical.