Formaldehyde-Free

My name is Gu Zhixuan. Three years ago, I enrolled at Jianglin High School, the city's top public high school. Throughout middle school, I had focused on art, though my academic grades were also quite good. However, the extra points from my specialty were never utilized.

The first month of high school was a whirlwind of chaos. My home was a twenty-minute drive from school, so I had to wake up at six every morning. With new teachers and classmates, I, being socially awkward, kept to myself in the back corner of the classroom. During the summer break, my parents enrolled me in a tutoring class, and I did fairly well in the selection exam, which landed me in the math competition class. Suddenly, I was overwhelmed with piles of incomprehensible test papers and handouts. Saturday afternoons spent in math competition classes marked the beginning of this story.

The first lesson was an introduction to plane geometry. The teacher gestured animatedly on stage, while I sat baffled, trying to grasp concepts like centroids, perpendicular bisectors, the power of a point, and Ptolemy’s theorem.

When class ended, some classmates rushed out to the vending machines in the corridor to buy drinks, while small groups gathered to discuss the problems. I didn’t feel like doing anything, so out of habit, I pulled out my sketchbook and charcoal pencil, intending to make a quick drawing during the twenty-minute break—yes, I still had to go to art studio on Sundays. My art teacher of three years liked my work and encouraged me to continue, but warned me that I couldn’t keep going like this forever, or else... I might perish. I had to choose between the study of form, lines, light, and shadow, and the world of shapes, formulas, equations, and molecular structures.

My mind was a tangled mess, but I started sketching nonetheless... Suddenly, a voice behind me exclaimed, “Wow!” Startled, I nearly jumped out of my seat.

“So amazing! Are you an art student? Your pencil grip is impressive too!”

“Impressive, my foot,” I thought, inwardly rolling my eyes as I cautiously turned to look at the girl who had spoken to me—she was quite beautiful. It was embarrassing to admit, but whenever I saw a pretty girl, my eyes would involuntarily fixate, sometimes even breaking into a strange smile. To avoid being noticed, I struggled between bowing my head to hide it and sneaking a quick glance. Her bright eyes were the color of the evening glow. She held a thick book, with a call number label from the school library on its spine.

“What are you reading?” My curiosity about books outweighed my shyness, and I asked.

“Ah, I got tired of math and wanted to change gears during the break—‘General Biology.’ It’s really interesting.” She showed me the cover, adorned with yellow flowers.

I leaned in to look. The illustration titled “Cell Metabolic Pathways” depicted nodes and loops intricately connected and entwined, like a Kandinsky abstract painting.

So beautiful.

“Ah, what’s your name? Can we be friends?” the girl tilted her head and asked.

“...Gu Zhixuan, Class Two.”

“Ling Quan, Class Three.” She closed ‘General Biology’ and solemnly extended her hand toward me. My face warmed; I lowered my head out of habit and then gently, almost symbolically, shook her slender, graceful hand.

The class bell rang.

“...Looks like we’re already over ten minutes late. I think everyone’s done for today... we’ll leave this problem for next week.” The teacher slammed the chalk into the box, leaving a half-drawn similar triangle on the blackboard, as if silently lamenting the unfinished lesson.

I was just about to reach the part I didn’t understand! I stared at the blackboard but could find no new insight. It felt suffocating to be left hanging like this. Why exactly were these two angles equal?

Maybe some students could solve it, but among all these unfamiliar faces, I didn’t recognize a single one. Wait—there was the girl behind me, Ling Quan. Perhaps I could ask her. I turned around; she sat expressionless, gazing out the window at the setting sun while calmly packing her things. Hesitantly, I tapped her desk with my handouts. She seemed startled, abruptly lifting her head, then instantly smiling brightly. That smile had a strange magic, easing my nervousness.

“Could... could you tell me how to prove this similarity?” I stammered.

“Ah... give me a piece of paper.” I quickly handed her paper and pen. She took them and swiftly wrote out equations while explaining:

“You’ve already proven these two triangles are similar,” she said, then pointed to another segment, “so their sides have this ratio. Then—this angle bisector means these two line segments are equal, which leads to this ratio. Plus the given angle—Q.E.D.”

“Eh? What’s Q.E.D.?”

“It’s *quod erat demonstrandum*, meaning ‘which was to be demonstrated.’ Sounds cool, right? ...Well, maybe not so much...” Suddenly aware of her own slightly pretentious behavior, she chuckled softly. Her clear, pleasant laughter echoed through the otherwise dull classroom.

I lowered my head and thought it over carefully, following her reasoning. In an instant, it all became clear. When I excitedly looked up to thank her, the girl had already packed up and quietly left, leaving only her departing silhouette behind.