A/N: This is the result of a conversation on Tumblr. I got really excited about something I saw on Rhinocio's blog and decided to make into a reality. So now this oneshot exists. The only thing I am sorry for is if I completely butchered roller derby in this interpretation of it. I did do some research, but that doesn't make me an expert by any stretch of the imagination. I did try, though!

Fun fact: The protagonist's perspective is kind of lazy, so they don't talk about anyone looks unless they think there's something interesting to point out, but I love the headcanon that everyone would be a POC if they were human, so that's totally a thing here. :)

Ruby leans her elbows on the desk and scrubs at her face without caring that it's knocking her red rimmed glasses askew. She loves this club, but sometimes…

"The individual stats are highly variable, but the basis upon which we'll be making calculation is consistent enough to make this excellent training," club president Pearl decrees with flourish. "Calculating speeds, trajectories, and inevitable collisions in real time will be good practice for the competition!"

"The only reason you want to sneak in and watch roller derby practice is because Rose Quartz plays," Ruby says flatly.

Pearl flushes. It's actually an impressive red, for someone with her dark complexion. "We are not sneaking in, Ruby," is the predictable, withering reply. "I got permission from the team captain to do this two days ago."

"The team captain is Rose, Pearl—and maybe she's too naïve to see it, but this is goddamn creepy. You've been hanging out since the beginning of last semester, and you can't stop talking about her or coming up with excuses to smash two very different clubs together. Just ask her out already."

"Thank you!" bursts out vice-president Peridot.

The rest of the club mutters their agreement. It's not that anyone dislikes Pearl, but they're a pretty close-knit group, and everyone's getting pretty tired of the wistful-Rose-talk.

Pearl, still very red in the face, gives Ruby the evil eye from the front of the clubroom, which is really classroom 218 in Gist Hall. "We're going," she says. "If you don't like the activities I design for this club, then by all means, give me an injunction. I'm sure Peridot, who would be acting president in the interim, would love all of the paperwork that comes with filing for grants so we can go to nationals."

There is a somewhat tense pause as everyone looks to Peridot for a rebuttal.

Peridot herself is visibly gnashing her teeth—Ruby can hear the complaints from here, 'this isn't orthodox, it's a waste of time, is this even legal for our club to do?'—but her hatred of the backseat filing Pearl would inevitably be doing, should she take over the club's paperwork, forces her to bite out, "We're sneaking into roller derby practice, and that's final. We'll see you all at the roller track by the west gym at six o'clock tomorrow. Bring notebooks, but no calculators."

This, Ruby thinks as she slings her backpack over her shoulder, is going to be a complete waste of time. Damn these mandatory club activities.

.:;;:.

It's not Ruby's intention to arrive early, exactly. That's just when the bus drops her off on campus. Besides, the late summer sun is still shining. Kipping out on a bench and soaking up some vitamin D whilst doodling about in her booklet of GRE math problems for the next twenty minutes won't kill her.

She hasn't hijacked a bench for five minutes before she hears, "Nice letterman."

Ruby glances up to see a petite young woman with a duffle bag and a waist-length braid. It's a soft blonde color that's streaked violently with blue, and her bangs curl away from her delicate cheekbones with a natural wave.

She's wearing short shorts and knee high socks. She has really nice legs.

"Thanks," Ruby says, keeping her eyes firmly above the shoulder.

The woman doesn't seem to notice Ruby's lack of conversational effort. "I haven't seen you around the west gym before. Are you a new athlete?"

To be fair, this isn't a terrible assumption. It's still the first month of the fall semester, after all, and new faces are everywhere.

Ruby laughs anyway. "Not even close. I'm an Eternal Flame, baby."

She pops open the snaps of her university-colored letterman and peels her suspender straps to the side to reveal the full glory of the official Mathlete Team shirt, The Eternal Flames: if anyone can construct indisputable mathematical proof of infinite combustion, it's us.

The team name is a bit of an inside joke.

The blonde woman scarcely blinks. "Oh, you must be one of Pearl's friends! Rose mentioned you all were going to sit in on our practice today."

"Yeah," says Ruby, snapping her suspenders back into place. "That would be us."

"Why?"

Preaching to the choir, sister, Ruby thinks.

"Because apparently we're supposed to calculate when someone's going to fall over before they actually do, for training," Ruby says. She thinks she does a fairly good job of keeping her private exasperation out of it, for the most part. It's not the rapidfire calculations that bother her—those might actually be fun—it's Pearl's ulterior motives that make her want to punch something. Ruby believes in honesty, you know?

"You can do that?" asks the rollergirl.

"Sure, if you run the problem fast enough."

"Is that something we could use to help with strategy, do you think?"

"Not unless someone is alarmingly consistent, no."

The woman makes a sound of disappointment. "Well, anyway. I'm Sapphire. My derby name is Nice Ice. Good to meet you…?"

At first Ruby waits for her to finish her sentence. Then she realizes why she's trailed off and introducing herself with a sheepish handshake.

"Why are you here so early, anyway?" asks Sapphire. "The rest of your club won't get here until six."

"The rest of my club has their own cars. I don't." And Ruby gestures vaguely in the direction of the University's bus depot.

Sapphire makes a small 'oh' of realization. "I should have guessed."

"Do you also take the bus?"

"No. I like getting a few laps in before everyone else gets here."

"Oh. Well, don't let me keep you." Ruby can respect a stolid dedication to your passion. Just because Sapphire's isn't math doesn't mean it's any less legitimate. She crosses her legs at the knee and scratches her thigh through her corduroys as she goes back to her GRE booklet.

Well, tries to. With her eyes lowered like this, she can see those legs in her peripheral. It should be illegal to show off legs that gorgeous.

"Actually," Sapphire begins, and Ruby's head snaps up guiltily. "Do you think you could figure out my averages?"

"What, like average speed?"

"Average speed, average start and stop times, the minimum amount of space needed for each—that sort of thing."

Ruby blinks. "Roller girls care about that sort of thing?"

"I do."

"But don't you have stop watches and coaches for this sort of thing?"

"Yes, but I haven't checked my stats in a while, and didn't you say you needed the practice?"

Well, there is that.

Ruby closes her GRE booklet and stands. If a pretty girl is asking her to hang out, who is she to say no? "Yeah, okay."

Sapphire looks petite when you're sitting, but she's actually an inch and three quarters taller than Ruby. Damnit.

"Can I ask you something?" says Sapphire as they walk towards the skating rink shoulder to shoulder.

"Something else, you mean?" says Ruby with a small grin.

Sapphire rolls her eyes. They're blue. Very, very, blue. How has Ruby never noticed them before now? "Yes, something else."

"Shoot."

"Are you actually planning on going to grad school, or is that GRE math book just for fun?"

Ruby scoffs. "Both, obviously."

"Are you even close to getting your bachelor's?"

"I've only got three semesters left!"

Sapphire laughs, and Ruby instantly decides that it's the best freaking sound in the entire universe. So much so, that she almost doesn't hear the amused mutter of, "Why am I not surprised?"

.:;;:.

In hindsight, it's fortunate that Sapphire asked her to help figure out her most recent stats, because it gave Ruby time to ask perfectly legitimate questions like, "What does roller derby even entail, anyway?" That way, when the rest of the Eternal Flames get to the rink and the Beach City Roller Girls actually begin scrimmaging against each other, Ruby finds that she is not as lost as the rest of her team.

"I can't concentrate!" Peridot grumbles. She slaps the face of her notebook with her mechanical pencil. "Why the hell are they all bunched up and shoving each other in endless circles anyway? There's plenty of room to spread out!"

"The blockers are trying not to let the jammer through," says Ruby helpfully.

"Gesundheit."

"That just sounds like a non-PC gay joke," someone remarks.

"Or a birth control joke."

"Maybe," Pearl says, astutely picking up on the mathlete's confusion. "We should watch a couple of rounds so we understand what's going on, and then jump into our calculations."

Normally Ruby would protest that there's no need for any of them to understand what the hell is going on in order to figure out when someone is going to skate full circle around the rink, but in this case she finds that she doesn't really mind having an excuse to look at Sapphire and her fantastic legs as she shoves at her opponents and glides around corners with surprising grace.

There are five players for each side of the scrimmage. Two lines of four form, while Sapphire and a short but thicker young woman with wild purple hair hang farther back. A whistle blows, and the two lines immediately solidify into walls of flesh that Sapphire and the purple-haired girl promptly try to fight their way through (the pack, Ruby reminds herself; proper terminology is important).

"Buff Slayer, no elbows!" calls the team member that's acting as one of the five referees. "Into the penalty box!"

The penalty box is actually just a line of chairs off to the side, and Buff Slayer—a huge, powerful woman with vitiligo—drops into one with sullenly crossed arms. Suddenly, the pack doesn't seem quite so dense anymore.

Being small in roller derby has its advantages if you are trying to get through the jostling wall of people in your way, Ruby is noticing. Somehow Sapphire pops out of the pack and sails on ahead unscathed. A whistle blows and announces her as head jammer, whatever that means. The purple haired girl emerges belatedly and works hard to catch up, but Sapphire is already trying to, well, jam her way through the pack again. As soon as she breaks free she pats both hands on her hips, and the whistle blows again.

The pack immediately breaks apart and starts chatting amongst themselves.

"Nice Ice, I loved that hustle!" calls a woman about Buff Slayer's size as she skates nimbly over to offer a high five to the much smaller player. Her hair is bright pink, and immensely curly. It's Rose Quartz, but Ruby's pretty sure that her derby name is Briar Rose. "I hadn't noticed you were through the pack before you were back again—your speed is phenomenal today!"

"Thanks," Sapphire says. "But once we got Jasper out of the way it was a lot easier. I can't take credit for that."

"I'm choosing to take that as a compliment to my skills as a blocker!" calls the woman from the penalty line of chairs.

As if feeling the eyes on her, Sapphire glances up at the bleachers where the Eternal Flames are camped out. Ruby immediately feels like a dufus for being caught staring, but that feeling vanishes the instant Sapphire looks her in the eye and smiles.

Ruby flashes a supportive double thumbs up, and is rewarded with a small snort of amused approval.

"Ugh, I hate going against Nice Ice for head jammer," groans the woman with the purple hair. She also has a tattoo of a purple-tinted owl on her arm, Ruby notes. Go figure.

"You almost had me a couple of times, Owl Getcha," says Sapphire. "If I had actually fallen, it would have been no contest."

"That's true, you did almost lose your balance…"

"You maybe one of our newest teammates, Owl, but you're also one of the only players who can give Ice a run for her money," Rose says supportively. "It was a good jam." She claps her hands and turns back to the team. "Want to try another one?"

There is an enthusiastic and decidedly athletic response of approval, and as everyone gets back into position (sans Buff Slayer/Jasper; she apparently isn't done serving out her penalty time), Ruby finds herself interested in which tactical formation the pack will take this time around, and how the jammers are going to fight their way through it.

"I still don't get it," says Peridot, gesturing sharply with her mechanical pencil. "I don't even understand what I'm supposed to be looking at, much less how I'm supposed to calculate it!"

"I really thought that this would go better," Pearl admits, glancing at her own notebook (which is utterly devoid of notes, incidentally). "But I can't concentrate either."

There is a small snicker from a couple of their friends/fellow Eternal Flames. "Oh, gee, I wonder why."

"I don't think we have enough data to extract proper conclusions, either."

"Fifteen seconds to full circle," Ruby says as Sapphire forces her way through the pack again. She consults at the stopwatch she has running on her smartphone, and lets out a "Aw, yeah, in your face!" with a hugely enthusiastic fist pump when it turns out her calculations of Sapphire's velocity and corner cutting were spot on.

"What?" says Ruby when she notices that the entire club has begun staring at her. She nudges her glasses up her nose and holds up the equation she's mocked up for jammer calculations. "This is what we're supposed to be doing, isn't it?"

"How did you…" Pearl snatches the notebook and pours over Ruby's notes, visibly reads it through twice, and then looks back to the current roller derby jam. "This makes sense, but I just can't—you made sense of all that?" And she gestures to the roller rink with Ruby's notebook.

"Sure. It's not a hard game, once you learn the rules," says Ruby. "Actually, this combination of offense and defense is a brilliant mental exercise. It changes all of the strategies you need to use!" When this is also met with nothing but blank stares, she says to Pearl, "You mean to tell me you've been spending all this time with Rose, and you've never taken the time to understand the sport she plays?"

Pearl is silent for a moment, scowling at being called out. Ruby has to admit, it is a little cruel to be pushing her this hard not even 36 hours from the last time, but at the same time…

Ruby is a little surprised when Pearl squeezes herself in between herself Peridot. She slaps Ruby's notebook down between them. Her honey brown eyes are bright with determination, and there is a slightly red flush in the apples of her cheeks. "Okay, explain how you got these base calculations."

"Actually, yeah, I'd like to hear you break those down too," says someone else, sticking their head in and resting their chin on Ruby's shoulder.

"Ditto."

"Okay, if Ruby's digging this then I'm missing something."

After a beat, Ruby shrugs and just dives into the explanation. No better time than the present—besides, she has a feeling she'll be seeing a lot more roller derby in the future. Ruby isn't an avid sports fan, but she likes this one (and for more than just Sapphire's presence, incidentally, though that certainly helps).

And to think she thought Pearl was crazy for making them do this.