Chalk flew on the back blackboard with wonderful curves and geometric patterns, as beautiful as an artist completing a shocking painting, Zhou Junlan looked at Ke Yuhan with a daze, and the board book in his hand also stopped unconsciously, and he was more convinced of the correctness of his decision.

After slowly and accurately depicting the last exponential curve, Ke Yuhan smiled and stepped away, dusting off his hands, leaning on the table to observe his creations on the blackboard, admiring the beauty of mathematics, lonely and determined.

"Is it okay?" Ke Yuhan turned her gaze to Zhou Junlan, but found that she turned her head to the board book in front of her in a panic, nodded, and said in a choppy tone: "Hmm...... Well, it's good, it's good."

The words she wrote were crooked, and then she erased them, but her trembling hands wrote more quickly, and compared with the previous writing, it was a world of difference.

Ke Yuhan found that during the period from the time he started painting to the 6 pairs of symmetrical exponential patterns that he had just ended, the board book plate that Zhou Junlan was in charge of did not seem to have changed at all, and seemed to be doing something else.

He returned to his place, picked up the water cup, and looked at the clock hanging in front of the classroom, it turned out that the two of them had been out of the blackboard for nearly 50 minutes.

"That...... Ke Yuhan...... Classmate, I called you to help me out of the blackboard newspaper today, it's troublesome. Zhou Junlan nodded at Ke Yuhan.

"It's okay, we're friends, we should."

The chalk in Zhou Junlan's hand suddenly broke, falling from above and smashing to the ground, with a crisp sound.

After Ke Yuhan finished speaking, he put down the cup and went to the bathroom to wash off the dust on his hands, at this time his hands were like a basin of flour.

Friend? Does Ke Yuhan really regard himself as a friend? Ke Yuhan has never ...... No, at least in the three years that Zhou Junlan has known Ke Yuhan, he has no friends, and even himself who is silently guarding in the dark will only be like a rain cloud hurriedly floating in the sky, when did he start to change?

When Ke Yuhan came back, most of the board book in front of Zhou Junlan was completed, the font was smooth and delicate, and he had only been gone for two minutes, and he couldn't help but admire Zhou Junlan's concentration when he was alone.

"Why did you find me to draw a blackboard newspaper? I mean, I didn't have any experience of painting either. ”

Zhou Junlan said: "Because of the theme of this blackboard newspaper, there seems to be some difficulty in it. The blackboard newspaper required by the school should be linked to learning, and it should reflect the beauty of learning, especially mathematics, but it is ...... in mathematics" She scratched her cheeks, but suddenly realized that she had chalk dust on her hands, and hurriedly wiped it off: "I really don't have any talent and ...... You can't experience beauty. ”

"Hmm-" Ke Yuhan nodded, and then said, "I didn't even know that you were the propaganda committee member of the class." ”

"It's okay, even if it's me, I was just nominated by the teacher today."

Zhou Junlan picked up the fallen half of the chalk, and under the relaxed atmosphere of chatting, her style was fluent. "The previous propaganda committee member in charge of the blackboard newspaper lied when filling out the form, saying that he had studied oil paint for 3 years, but in fact he didn't, so Mr. Wang fired him in a fit of anger."

"Did you learn to draw?"

"Hmm...... When I was in the fourth year of elementary school, my father sent me to a cram school to learn sketching. To be honest, I was pretty good at learning, but then the kids in the cram school thought I wasn't easy to get along with and ignored me, and I gradually stopped wanting to draw. ”

After saying these words, the book section in front of Zhou Junlan was also completed.

"The words are beautiful." Ke Yuhan replied behind the podium with a smile.

"Thank you."

After Zhou Junlan finished washing up from the toilet, Ke Yuhan drew a wonderful curve on the blackboard.

It is two spirals, respectively in the first quadrant and the third quadrant of the plane direct coordinate system, symmetrical about the origin, the edge of each stretches out two long lines, converge at the origin, the threads are like the pattern on the snail shell, until the center of the ring is a ring, the center of the ring points a point, if you have to compare, and the image of Tai Chi is somewhat similar.

"What beautiful graphics." Zhou Junlan stepped closer, not knowing whether she praised the graphics or Ke Yuhan's dexterity. "What's this function called?"

Ke Yuhan frowned, as if he had heard something incredible: "This is not a function, it is impossible for a function to have a one-to-many situation, presumably you didn't listen carefully in class." This pattern ...... "He dotted the blackboard: "It is called the horn spiral, also called the euler spiral, which is the most beautiful and representative of the spiral, and the term spiral comes from the Greek, and its original meaning is 'to wind' or 'wind'." ”

"Has this teacher ever taught?" Zhou Junlan searched for this mixed concept in her mind, suspecting that she and Ke Yuhan were not taught by the same math teacher.

"No, it's something I read from a book, like a little anecdote or something. But ......" Ke Yuhan leaned against the table, looking at the figure and pondering, as if watching a beautiful scenery that people would never want to leave, or being in a palatial palace. "It's really beautiful."

Zhou Junlan looked at Ke Yuhan's side face and felt that it was the beautiful scenery that made her heart move.

She wanted to say something, but she didn't know how to speak, maybe not speaking was the right choice, she had chosen to be silent for nearly four years, not missing a moment and a half.

But in the blink of an eye, I have doubts about my ability to grasp the opportunity, if I don't have the chance to be alone with him again, will I never have the opportunity to make friends with him again?

Next to her ears was the sound of her own surging heartbeat.

"The house is too big and empty."

"Huh?" Ke Yuhan was stunned for a moment, not understanding what Zhou Junlan suddenly meant.

Zhou Junlan smiled, then lowered her head and elaborated on the past: "You asked me a question. My mother, when I was three years old, left suddenly, without warning and without reason, and my father didn't seem to have any intention of staying, and the divorce procedures between the two went smoothly and without dragging. Every time I tried to talk to my dad about things between them, he would always tell me to leave them alone, saying that I was too young to understand. ”

Ke Yuhan listened carefully, her head lowered more and more, looked at the ground under her feet, and kicked a piece of paper under her feet: "Every six months, my mother will send me a letter describing her recent situation and sending back a photo of her, but she is never willing to tell me her phone number. Every photo, taken in a different place, seaside, mountains, temples, forests, every one, she smiled very happily. It is said that she travels, travels around the world, and she is the editor-in-chief of an international magazine and is not short of money. ”

"And what about your dad?" Ke Yuhan asked.

"After my father left my mother, I changed many girlfriends, but each time it didn't last long, and over time, I got used to it, so maybe......" She raised her head and pursed her lips, as if she wanted the tears in her eyes to flow back. Maybe it's because of this that I don't have enough self-confidence and become cowardly......"

"So ......" Ke Yuhan handed over a tissue, Zhou Junlan took it, and exclaimed in his heart that he was now able to observe his face and be considerate, and expressed his gratitude.

Ke Yuhan continued: "So this is the sudden change in the environment that you told me before. ”

Zhou Junlan was surprised: "Do you remember?" ”

Ke Yuhan nodded, "Well, the spiritual sustenance you told me before, the boy who supported you through that time......" He paused, as if thinking about whether his next sentence was reasonable.

"It's okay, you ask." Zhou Junlan said.

"You ......" Ke Yuhan turned around and looked at Zhou Junlan's eyes: "I'm curious, what kind of person can let others entrust all their beliefs to him, what is he...... What was done? ”

Zhou Junlan looked at Ke Yuhan's serious expression, and the corners of her mouth gradually curled, so she turned her face to the side, adjusted and turned back. Seeing his face again, he laughed louder and louder, and then, she laughed more and more cheerfully, bent over to cover her stomach, and squatted on the ground, she even smiled so softly.

"What are you laughing at?" Ke Yuhan stood in place at a loss.

Zhou Junlan wiped away the tears from the corners of her eyes, stared up at Ke Yuhan's face for a long time, and said, "I, I think, this problem, that boy, he himself doesn't know." ”