You Are the Code of My Heartbeat

Heartbeat Protocol

Cheng Jian woke at 4:18 AM.

There was no thunder outside, only the soft hum of the air conditioner. Lu Wan’s arm lay across her waist, her palm resting on Cheng Jian’s cotton pajamas, warmth seeping through the fabric into her skin. Carefully, Cheng Jian lifted her hand away — a motion she had perfected over the past three months. Now, she could do it without waking Lu Wan 87% of the time.

That number was precise down to the decimal because Cheng Jian had, in fact, been keeping track.

She stepped barefoot onto the cool floor and walked toward the desk. The computer screen lit up in the darkness, casting a pale blue glow on her face. The terminal window was still open from last night, the cursor blinking beside an incomplete function definition:

def handle_heartbeat():

"""Handle abnormal heartbeat signals"""

Cheng Jian stared at the comment for a few seconds, then hit backspace and typed again:

def handle_heartbeat(sender):

"""Allow heart rate to exceed threshold when sender=Lu Wan"""

As she saved the file, a rustling sound came from behind. She turned to see Lu Wan rubbing her eyes in the doorway, holding the gray wolf plushie — now named "Debug," written neatly in marker on the tag’s back.

"Another insomnia episode?" Lu Wan’s voice was thick with sleep, like a mouthful of cotton.

Cheng Jian closed the laptop. "Yeah."

Lu Wan shuffled forward, handed Debug to Cheng Jian, then reached for a small bottle on the bookshelf. The scent of lavender oil filled the air as she warmed her palms and gently pressed her fingertips to Cheng Jian’s temples.

"This is a new blend," Lu Wan whispered, her breath brushing against Cheng Jian’s ear. "With cedarwood."

Cheng Jian closed her eyes. There were thin calluses on Lu Wan’s fingers from years of holding pens — subtle friction as they massaged her temples, like sandpaper smoothing frayed nerves. It occurred belatedly to Cheng Jian that she could now identify exactly where each callus came from: the side of the index finger from the stylus, the first joint of the middle finger from pencils, and the palm from paint scrapers.

"All done," Lu Wan patted her shoulder. "Time for bed."

Cheng Jian was half-led, half-guided back to the mattress. As usual, Lu Wan slid under the covers, placed Debug between them, and pulled Cheng Jian’s wrist to rest on her waist — a sleeping position she’d invented last month, claiming, “Skin-to-skin contact boosts serotonin.”

At the time, Cheng Jian had checked the literature and found the claim wasn’t entirely accurate — but she hadn’t argued.

Now, she could feel the rhythm of Lu Wan’s breathing clearly. The pajama fabric was thin, and body heat passed through without resistance — like holding a piece of warm jade. Cheng Jian counted Lu Wan’s breaths, reaching seventy-three before drifting off to sleep.

---

Saturday morning brought the smell of something slightly burnt to Cheng Jian’s nose.

She walked into the kitchen to find Lu Wan in an apron, frying eggs with her hair messily twisted into a bun, strands still streaked with blue watercolor from yesterday’s late-night painting session. On the counter sat a collection of pancakes — some charcoal-black, others golden and perfect, clear evidence of multiple trials.

"Morning!" Lu Wan turned around, flour on her nose. "I did it!"

She held out a plate with one nearly perfect pancake — crispy edges, fluffy center, drizzled with amber maple syrup. Cheng Jian took a bite. The sweetness balanced perfectly with the wheat aroma.

"Good," she said objectively.

Lu Wan’s eyes curved into crescents. "See? The seventh try paid off!" She leaned in to watch Cheng Jian chew, suddenly reaching out to wipe a drop of syrup from the corner of her mouth. "Did you know, Cheng Jian, that when you eat something you like, your right eyebrow lifts just a little?"

Cheng Jian froze. She hadn’t known that about herself.

"And also," Lu Wan added smugly, "when you’re stuck on code, you bite your lower lip. And when you fix a bug, you let out this tiny sigh — like this." She mimicked a short exhale, uncannily accurate.

Cheng Jian put the fork down. "You observe too closely."

"Of course," Lu Wan turned off the stove, "you're my most important..."

The end of the sentence disappeared into the sizzling of the pan. Cheng Jian watched her back, noticing how Lu Wan’s ears visibly flushed red. That realization made her smartwatch vibrate again, and a familiar warning appeared on the screen:

`Warning: Heart Rate Exceeds Threshold`

This time, Cheng Jian didn’t hit “ignore” like usual.

---

In the afternoon, while organizing her code, Cheng Jian discovered a newly created database table named `habit_records`. The field list made her pause:

- `subject_id`: 1

- `eye_blink_freq`: 3 times/minute (during lying)

- `lip_bite`: BOOLEAN (true = facing difficulties)

- `eyebrow_raise`: FLOAT (0.3 cm = pleasure)

The last recorded timestamp was this morning at 9:47, with a note:

「Pancake experiment successful! Syrup measured precisely to 5ml」

Cheng Jian stared at the screen, feeling an unfamiliar warmth rise up her neck. These records were deeply personal, precise to the millimeter and milliliter — yet oddly, they didn’t feel intrusive. She opened the terminal and created a new table called `reciprocal_records`, typing:

- `subject_id`: 2

- `ear_redness`: INT (color code #FF6B6B = shyness)

- `hair_color_stains`: VARCHAR ('Cobalt Blue' | 'Burnt Sienna' | 'Madder Red')

- `hum_freq`: 2.4 times/hour (while focused on drawing)

As she saved, she heard Lu Wan humming softly in the living room — off-key, but hitting exactly 2.4 notes per minute. A small smile tugged at Cheng Jian’s lips as she added another line to `hum_freq`:

「Pitch rises when she fails — like a cat whose tail got stepped on」

---

At ten PM, Lu Wan curled up on one end of the couch with her digital tablet, sketching. Cheng Jian sat on the other side debugging code, with Debug the plushie wedged between them. The AC blew a cool breeze, lifting loose strands of Lu Wan’s hair, one stubborn curl clinging to her lips.

Cheng Jian watched it three times before finally setting down the laptop and reaching over to tuck the strand behind Lu Wan’s ear.

Both of them froze. Lu Wan’s ears flushed instantly, matching color code `#FF6B6B`; Cheng Jian’s hand hovered midair, fingertips still tingling with the memory of soft hair — like moonlight slipping through fingers.

"Finished coding?" Lu Wan asked quietly, eyes still on the tablet.

"Yeah." Cheng Jian pulled her hand back. "Optimizing algorithms."

Lu Wan nodded and suddenly turned the tablet toward her. "Like it?"

On the screen was a half-finished illustration: a hoodie-clad programmer holding the Debug plushie, speech bubble above their head not filled with code, but a simple hand-drawn heart. Scattered across the background were various elements — caramel pudding, a succulent plant, pancakes, lavender, and a tiny thermometer reading 28°C.

Cheng Jian swallowed. "What is this…?"

"Our merchandise design!" Lu Wan pointed excitedly at the details. "Look — Debug has paint stains on his paws, your sleeve has syrup marks, and here—" she zoomed in on the bookshelf in the background, "—I drew all your programming books."

Cheng Jian studied the details. Not only had Lu Wan remembered every book on her shelf, she'd even captured Cheng Jian’s unconscious habit of running her thumb along the edge of pages while reading — perfectly recreated in the illustration.

"Do you like it?" Lu Wan asked, her voice suddenly softer.

Cheng Jian looked at the illustrated version of herself — a rare tenderness on her face, never seen in real life. She thought of the modification she’d made in the health monitor: `When sender=Lu Wan, allow heart rate to exceed threshold`.

"I do," she said, feeling her wristband vibrate again. This time, she didn’t check the warning.

---

Before bedtime, Lu Wan blow-dried her hair in the bathroom. While making the bed, Cheng Jian found a note tucked under the pillow, in Lu Wan’s handwriting:

「Cheng Jian's Heartbeat Records (Encrypted Version)

- First Over Threshold: 6/18, I fed you pudding

- Highest Record: 7/3, when I touched your wrist

- Longest Duration: 7/15, while I dried my hair

P.S. Don't delete the `/sunshine/` folder — that's my favorite project」

Cheng Jian slipped the note back under the pillow, then opened her laptop and added a new entry to the `reciprocal_records` table:

- `note_hiding_skill`: 0/10 (always hidden under the bottom-right corner of the pillow)

Then she created a new folder named `/moonshine/`, dragging in today’s photo of Lu Wan drawing — the side profile, soft lighting, paint-streaked hair. The filename followed Lu Wan’s format: `20230728_26℃`, with a small crescent moon symbol added at the end.

When the bathroom door opened, Cheng Jian quickly shut the laptop. Lu Wan climbed into bed, bringing the scent of lavender with her, damp hair dripping slightly and pushing Debug to the foot of the bed.

"Night," she mumbled, as always wrapping Cheng Jian’s wrist around her waist.

Cheng Jian didn’t pull away. Moonlight spilled through the window as she listened to Lu Wan’s breath slow into sleep. For the first time in a long while, she realized — she hadn’t counted any prime numbers tonight.