Work Text:
“In the third dimension,” Baekhyun said, turning his swivel chair side to side and casting a blinking shadow on Kyungsoo’s face where he lay in bed, “we use vector-valued functions as opposed to real-valued functions, which means that the output isn’t a real number; it’s a vector. What’s interesting about it, though, is that a lot of how we evaluate real-valued functions is similar to how we evaluate vector-valued functions. For example…” Pause. Kyungsoo jolted back into focus when he realized Baekhyun was looking at him.
“For example?”
“Am I keeping you up? I mean, I obviously am. You can go to sleep.”
“No.” But he yawned before he could stop it, rubbed his eyes before it caught up to him that the gesture didn’t do much to prove his point. “Keep going.”
They were in Baekhyun’s side of the room. The two of them were roommates in the dorm they shared on campus, a small but cute place with half a wall dividing their beds and desks. The wall was meant to give some sort of privacy to two roommates, but they had a habit of spending time on one side. This time, it was Kyungsoo on Baekhyun’s side, lying on his bed while he listened to his lecture on some math stuff he didn’t get.
It had become familiar at this point, listening to Baekhyun drone about numbers. For a design major like Kyungsoo, it all went over his head. Nevertheless, he humored his roommate for very specific reasons that he didn’t feel like getting into at ten in the evening, early for Baekhyun but late for him. The main reason, or what he would say if Baekhyun were to ask, was because it helped Baekhyun study. Baekhyun liked teaching to learn. Kyungsoo didn’t have much else to do but help, when he wasn’t busy doing his assignments or convincing Sehun he wasn’t dead, he was just… spending a lot of time in the dorm.
He stayed there a lot. Not for any particular reason. Just to do his work and nap and, on occasion, listen to his roommate talk about vectors.
“Go to bed,” Baekhyun said, fondly. “It’s late for you. I promise I’ll be quiet, so sleep.”
Stubbornly, Kyungsoo hugged Baekhyun’s pillow and propped his cheek against it in a firm message that he wasn’t moving. “Just continue. I’m invested now.”
A small laugh came in response. “Invested?”
Kyungsoo blinked sleepily. “Mhm.”
“Okay, then. But don’t say I didn’t give you an out.”
Baekhyun chuckled again when Kyungsoo hummed a reply, and turned back to his computer to continue his lecture. Kyungsoo really tried to listen. He really did, but it was all just a bunch of nonsense to him without any background in the subject. Eventually he felt himself drifting, and before he knew it, he was waking up to Baekhyun putting his blanket over him.
“I was listening,” Kyungsoo mumbled.
“Uh-huh.”
“I really was.”
“Sure you were.” Baekhyun ruffled his hair with a soft laugh. “Just sleep already. I’m done studying now.”
“I’ll move. I stole your bed.”
“No, it’s fine. I’ll just take yours.”
No sense in arguing. Besides, he was already falling asleep again. “Good night.”
“Good night, Soo.” And then, after a pause, “Thanks.”