> Tau Do I Love Thee?
>  by YoshiFawful64
> --------------------------------------------------------------------------

> Pining for You
> --------------------------------------------------------------------------

"Okay, Sunset. You can do this," Sunset Shimmer said to herself as she approached the front yard of Canterlot High, where she knew Twilight would soon show up as well, the school day having ended a few minutes ago. Everything was ready. It had taken some time after Twilight had transferred from Crystal Prep for Sunset to realize that she was developing a crush on her, and some more to come to terms with it. Then she'd needed to gather up the nerve to actually do something about it, and come up with the best way to do so. Now, at last, she was ready to make a move. She'd even confided in Spike beforehand, so he'd know to leave the two alone.

The timing was perfect, too, what with that night being the date of the slumber party the girls and Spike had been planning at Applejack's place — if everything worked out, they could announce the good news to everyone. If not… well, at least she'd be around plenty of people willing to comfort her. And Rainbow Dash would be there too, she supposed.

And yet, she couldn't help but feel nervous — more nervous than she felt she should, in fact. It's not like she hadn't dealt with rejection before. Maybe it was because her friendship with Twilight and the others was still so new and precious to her that she was afraid of risking it, or maybe she was just less carefree than she was all those years ago. Whatever the reason, her heart kept pounding, and she struggled to keep a calm expression.

The front door of the school building opened, letting a mass of students pass through. Twilight was the last out, having stayed back to avoid being caught up in the crowd. She smiled as she saw Sunset wave at her, and they united as the other students began to disperse. Soon, the two girls were left alone in the yard.

A muffled voice let Twilight know that Spike wanted to be let out of her backpack. Once Twilight had opened the zipper, the dog hopped to the ground. "Hey, Twilight, I need to go. I promised Pinkie I'd lend her a hand — er, paw, with the preparations for the slumber party."

"Are you sure you can get there safely by yourself?" Twilight asked.

"Of course! I'm not exactly an ordinary dog anymore, after all."

"I suppose not. Still, don't forget to be careful!"

"I won't. You girls have fun! I'll see you at AJ's place!" Spike called out as he ran off. Just before turning around the corner of the school, he stopped briefly to give Sunset an encouraging wink and what seemed like an attempt at a thumbs up.

Sunset took a deep breath to calm herself. This was the moment she'd been waiting for. "Hey, Twilight, I've got something for you," she said as she opened her own backpack.

"Oh? What is it?"

"Here you go." Sunset handed Twilight a handmade card.

It was a rosy pink, with a fractal pattern made of hearts. In the middle, written with a bright red ink in Sunset's prettiest handwriting, were the words "Are you tau?" Twilight opened the card, revealing the rest of the message: "Because you're beautiful and transcendental, and everything makes more sense with you."

A moment of silence passed, with an expression on Twilight's face that Sunset couldn't read. She started feeling nervous again. Was the card too cheesy? Was she coming on too strong? Were the compliments too exaggerated?

Quietly enough that Sunset only barely heard it, Twilight said, "Oh no." She then turned to Sunset, saying, "Don't tell me you're one of those people."

Sunset blinked. "Huh?"

"Please tell me you're not a tauist."

Slightly indignant, Sunset said, "I'm sorry, what?"

"I mean, how could you possibly think that pi, one of the most famous and beautiful numbers in mathematics should just be… cast aside like that?"

Sunset's eye twitched, her panic from a moment before turning into irritation. "Well, excuse me, Twilight, but I was under the impression that math is supposed to be as useful and elegant as possible," she said, injecting as much sarcasm into her voice as possible.

Twilight narrowed her eyes. "Oh, is that why you're willing to just throw the first non-algebraic number ever discovered under the bus?"

"Oh, for the love of— Just because pi's more conventional, that doesn't mean it's better! Tau could remove so many unnecessarily convolutions, not to even mention making math easier to learn!"

"Well, if you'd like to claim that pi should be replaced, then I expect you're ready to argue your point!"

Sunset's mouth drew into a snarl. "Oh, you bet your pretty little head I am."





"And how about Euler's identity?" Twilight yelled. "Do you suggest we simply abandon what is one of the most elegant equations in all of mathematics?"

"Actually," Sunset hollered back, "I want to make it even more beautiful! e to the power of i tau equals one, and by separating the exponent into fourths, we get the powers of i! Which, in case you didn't notice, represents a unit circle in the complex plane!

Twilight's rebuttal faded into the distance as an exasperated Rainbow Dash walked upstairs and away from the Apples' kitchen. "So, would you mind explaining exactly what they're going on about?" she asked Spike, who had been trying his best to read a book. "In non-colossal-nerd terms, please."

Spike sighed. "Well, you know what pi is, right?" he replied. "A circle's circumference divided by its diameter, approximately three point one four? Never ends, never repeats itself, all that?"

"I have a rough idea, yeah. It shows up a lot in advanced math stuff, right?"

Spike nodded. "See, thing is, there's some people — and apparently Sunset's one of them — who think that pi is actually more inconvenient than it should be. According to them, it would be more useful to use the ratio of a circle's circumference to it's radius instead. They call that number, which is also two times pi, by the name 'tau'."

"And... why, exactly, are Sunset and Twilight at each other's throats over this?"

"I'm not really sure, actually," the dog admitted. "I guess they just got into an argument about it, a few less-than-friendly words got said, and it just… downspiraled from there."

"Huh." After a moment, Rainbow gave him a curious look. "Actually, Spike, how do you know so much about math even though you've been a regular dog for most of your life? Did you just get all that when you got zapped with magic?"

"Oh, I'm sure that played no small part in it, but I don't think that's all of it. I mean, keep in mind that I was raised by Twilight, of all people," Spike said with a smirk.

"Heh. Leave it Twi to teach math to her dog."

Spike chuckled. "Oh, you don't know the half of it."





Twilight seethed. "So, what? You're saying we should throw out every single textbook that uses pi, and replace them with ones that use tau?"

"No, I'm saying we should slowly phase tau in! And it could help so many people learn things like trigonometry more easily!"

"Oh, is that why you failed that geometry question in the Academic Decathlon?"

Sunset's nostrils flared. "THAT WAS BECAUSE I WAS STRESSED AND MADE A TYPO, AND YOU KNOW IT! AND WE WEREN'T EVEN ALLOWED TO USE TRIGONOMETRY FOR IT!"

Twilight prepared to shriek something back—

"ENOUGH!"

Twilight and Sunset turned to look at the source of the yell. Fluttershy, whom they hadn't noticed due to the heat of their argument, looked frazzled.

"Now, it's perfectly normal to have disagreements with your friends, and that's okay," she said with a deep sigh. "But you two—" she pointed an accusatory finger at Sunset and Twilight, "—have been yelling and screaming at each other for several hours now, and only because of math. Because you can't agree on what number to use, and that's apparently a good enough reason to keep everyone else awake."

Fluttershy glared at the other two girls, who avoided eye contact with her and each other.

"Now, I want you both to apologize to each other and make up."

Twilight looked at her feet. "…I'm sorry. I guess that got a little out of hand."

"You weren't the only one blowing it way out of proportion," Sunset replied gingerly. "I was just as much at fault as you were, and I'm sorry too."

"Good," Fluttershy said. "Now, if you'll excuse me, I am going to sleep."

With that, she promptly turned around, walked up the stairs to the bedroom, and shut the door.

A moment passed in an awkward quiet.

"Hey, Sunset?" Twilight asked.

"Yes?"

"I know this wasn't exactly a very good debate on whether pi or tau is better, but you actually made some pretty good points back there. So, a little later, could we maybe have a proper conversation on this? I'm actually kind of interested in discussing it. Just, you know, without all the shouting."

Sunset smiled. "I'd like that. And speaking of shouting…" she nodded her head towards the bedroom door. "Five bucks says that Fluttershy's gonna spend at least an hour apologizing to us next morning."

"Sorry, I'm not in the habit of taking bets that I know I'm going to lose," Twilight responded with a chuckle. "I really didn't expect her to burst out like that, though. She seems way too… gentle to do that."

"It caught me off guard too, but I guess everybody has a limit. We were pretty loud, after all." Sunset thought of something, then grinned. "I suppose you could say we got a little… irrational."

Twilight snorted in laughter. "Yes, we were a tad too pious about our stances."

"We shouldn't have gone to taun on each other like that."

All the tension that had been building between Sunset and Twilight melted away as they shared a laugh.

"Actually, all these puns remind me…" Twilight rummaged through her backpack. "What was it that you wrote on this thing again?" She pulled out a pink, familiar-looking card. "It was actually pretty clever, if I remember correctly."

A sudden panic swelled in Sunset's chest. "No, you don't have to look at—"

"Now that I think of it, why did you give me this in the first pla—" Twilight looked at the card as though for the first time, her eyes tracing the flattering words and heart shapes upon it. "Oh." She blushed. "R-Right."

Sunset stumbled for words. "Twilight, I, uh… I can sleep on the couch if you're uncomforta—"

"Wait," Twilight said. "If… if you're asking what I think you're asking…" she said, as her face turned red enough to rival Sunset's hair. "Then the answer is yes."

It took a moment for Sunset's brain to process that. "Really?"

Twilight attempted to collect herself, and her cheeks regained some of their usual colour. "Well… apart from my brother and Spike, I may be pretty new to actually having friends, let alone…" — her blush returned in full force — "Dating, but I think… I would like to try it." She looked at Sunset. "With you."

Sunset smiled softly. She offered her hand to Twilight, who took it. She then closed the distance between them, and gave Twilight a small peck on the cheek. For a moment, they stood there together in a comfortable silence.

Then, Twilight brought her free hand up to her mouth, yawning.

This caused Sunset to yawn, too. "Guess we'd better head to sleep, huh?"

"It is getting pretty late. Plus, we can share the good news with everyone. Er, no math pun intended this time."

Still holding hands, the two girls climbed upstairs, and went to open the bedroom door — only for Sunset to immediately get smacked in the face by a pillow that Rainbow Dash had tried to throw at Pinkie Pie.

Inside the room, Rainbow, Pinkie, and Applejack were engaged in a furious pillow fight. Spike, too small to throw pillows around, was spectating eagerly and cheering everyone on. Fluttershy, somehow, was asleep despite the ruckus.

Sunset slowly picked up the pillow that had hit her.

She and Twilight turned to look at each other and grinned.

Then, with a dual battle cry, they charged into the room, joining the brawl.