//------------------------------//
// Discovery 
// Story: Layers 
// by Trick Question 
//------------------------------//

"Twi?" said Starlight Glimmer, shaking Twilight Sparkle awake in her throne.

"Huh? Oh, ugh. Sorry," replied the princess, pushing her marefriend away with a hoof.

"You were sleeping in an uncomfortable throne."

"I... I woke up and couldn't get back to sleep. I'm sorry, Star."

"It's okay. The important part is that we tried," said Starlight, nearly suppressing a grimace from her face. "You could have gone and slept in my bed, though. Or any of the dozen guest rooms we have prepared."

"Yeah, I know. I just couldn't stop thinking about the e-Quine."

Starlight smiled. "You have to admit, the name is catchy."

"Better that than 'cascading set of universes we created like a pair of ignorant, foalish gods'," said Twilight. "Er, no offense."

"None taken. I don't feel too guilty, anyway. There was no way we could have predicted a recursive spell would generate a copy of our universe, much less what must be untold millions of copies by now. If not infinitely many."

"It's hard to believe a spell so simple could have such an extraordinary effect. It'd be easy enough to check that it isn't somehow just a view of our own universe by casting a spell into the simulated universe, but we'd have to break symmetry to do that," said Twilight, "and the act of breaking symmetry could cause the next universe to become real. It's kind of a Catch-22."

Starlight sat up in Applejack's throne. "Hope AJ doesn't mind me keeping her seat warm, heh," said Starlight.

"You deserve a throne here too," said Twilight, smiling tiredly. "I still believe the Tree may grow one for you in time."

"Eh, I'm just happy to be loved." Starlight noisily cleared her throat. "Anyway, I stopped in the library before coming down here, just to test something."

"Starlight! I don't want you doing anything by your... well... I guess it's fine," said Twilight, lowering her eyes to the floor.

"No, I should have waited for you. It was the tiniest little test you can imagine," said Starlight, rolling her eyes. "Argh. I knew it was a mistake not to include you!"

"What's done is done," said Twilight, with a sigh. "What'd you find?"

"I found out you can only go back in time to the point just after we cast the spell. The past thread of the simulated universe doesn't seem to exist before then. It must have borrowed the current state of the universe to begin the simulation," said Starlight. "After I ran the test, I returned it to the almost-present view of the cascading simulations. Staring into infinity is kinda fun."

Twilight laughed. "Yeah, I guess so. Though you're not looking deeper than one layer every five seconds after you reset it, y'know."

"Thanks for the technical correction, Mud Briar," said Starlight.

Twilight craned her head to the side. "The Sun out there is bright. How late is it now? Did you go pick up Sunburst already?"

"Horsefeathers!" cursed Starlight. "Oh, colt, I hope he hasn't been waiting long!" She disappeared in a burst of turquoise light.

"Ugh," said Twilight, as her smile disappeared and her head thwapped down onto the Cutie Map.

Moments later, Sunburst and Starlight Glimmer appeared in another flash of light, along with a set of suitcases.

"Urp," said Sunburst, holding his stomach. "Starlight, I'd have been fine with walking..."

"It's okay! Now you're here. Sorry for the wait. Really," said Starlight.

"Again, not a problem," said Sunburst. He shook his head and steadied his legs. "Oh, hello Twilight. I, um, didn't know if I'd see you here."

"I'm fine," said Twilight. "I mean, why wouldn't I be fine? You're fine. We're all fine here."

"Look, I understand there's some... tension," said Sunburst, rubbing the back of his neck with a hoof. "I want you to know I'm not here to get between the two of you..."

Starlight grunted. "I'm not going to have sex with him. There, now we can move on."

"I know you're not going to, even though you really want to—"

"That isn't what an open relationship is about, Twilight. It's about trust."

"Which is not what we have... er, not the trust thing. I mean we have a closed relationship."

"I don't need to have sex with him, Twi! I just want us to be able to have a child—"

"Which is what adoption is for!"

"I'm not afraid of losing you if you have sex with Sunburst. Why are you so..." said Starlight Glimmer. She paused and looked around, noticing Sunburst had already left.

"I'll find him and set him up with quarters," said Twilight. "Or he can stay in your room, I don't care. Because I do trust you, and that has nothing to do with opening our relationship to casual encounters."

"Twi, please don't be this way," said Starlight, closing her eyes.

Twilight sighed. "I'm sorry Star... I had a rough night. This was a really bad time to create an endless sequence of universes."

Starlight hooftipped at the floor. "We've been putting off this discussion for too long."

"I know. You're right." Twilight stood up and walked over to give Starlight a hug. "I'm just so afraid of losing you..."

Starlight placed Twilight's hooves in hers and looked into her eyes. "Nothing can make that happen, Twi. Can't you realize that?"

Twilight pulled her hooves away. "I'm trying, Star. I'm trying. Look, have him stay in your room. I insist." She bit at the edge of her lip. "So you probably want to tell him about our experiment, I assume?"

"Not because of this or anything. But he's the most knowledgeable mage in two kingdoms," said Starlight.

"I know. I agree he should be included."

"Let me go find him."

"I'll be in the library," said Twilight.





Twilight waited in the library for an hour before Starlight and Sunburst showed up.

"There you are. I was starting to think you'd fallen in the lake," joked Twilight, dryly.

"Ha ha," said Starlight. "Sunburst needed some time to himself."

Sunburst mopped some sweat from his brow. "I really don't want to be any trouble, Twilight."

"It's fine, Sunburst. None of this drama is your fault... it's mostly mine," admitted Twilight.

Stepping forward, Sunburst eyed the mana crystal, currently glowing with Starlight's aura, then examined the projection screen. "Amazing. You're positive this isn't just a video feed of the room?"

"See for yourself," said Starlight. "Just grab the crystal with your magic and move it with your mind."

"Easy as telekinesis," said Twilight.

"Even I can do it, huh?" said Sunburst, with a chuckle.

Starlight blanched. "She didn't mean that."

"I know, I know! Just a little self-deprecating humor to, um, lighten the mood?" said Sunburst. "Ugh, I'm terrible at this. Okay, let me see this thing..."

Sunburst's light yellow aura replaced Starlight Glimmer's turquoise around the mana crystal. The view zoomed out until the castle could be seen.

"This is amazing! And you can see anything with it?"

"As long as it happened after we cast the spell, and outside the tiny event horizon near the epicenter," said Twilight. "The spell is walled off from the outside world. That's how we know it's a simulation."

"This is incredibly powerful magic," said Sunburst. "We can't let this fall into the wrong hooves, Twilight. It's a perfect spying tool."

"But think of the research! We can see what stars look like, visit the Moon without needing a light bridge, even go to the deepest parts of the ocean floor!" said Starlight. "This has the potential to be one of the greatest discoveries since friendship."

Twilight nodded. "It's a blessing and a curse. But we need to understand it more, first."

"Hay, Twi," said Starlight, "didn't you have an idea about casting a spell into the simulation to prove it's a distinct universe?"

"I did. The mana crystal should be a one-way barrier. Focused magic can enter the crystal, but nothing else can enter or leave, apart from the viewport," she said.

"Sunburst, let me borrow that for a moment," said Starlight. Sunburst had since moved the viewport to examine a star: a large, flaming ball of rocky material attached to the Celestial Sphere.

The aura color changed to Starlight's turquoise, and after a minute of searching the castle came into focus again.

"There's a resistance when this thing isn't aimed at the present moment," said Starlight. "I don't think I can cast into it unless it's tuned to the now."

"I sensed that," said Twilight. "What are you going to cast?"

"Do you have a spare bit? I'll pay you back."

"Here," said Sunburst, pulling one from his saddlebags.

Starlight grinned and held the bit. "Since the mana crystal is a small-scale version of our universe, it should take much less energy to put something into the simulation than it would to teleport it from place to place on the outside. I can turn this single bit into a mountain of bits," she explained, then meandered the viewport into Spike's room. Spike was reading a comic book in bed and eating from a small bowl of gems.

"We shouldn't be seeing this, Starlight," said Twilight.

"Oh, he's not doing anything embarrassing," said Starlight. "Besides, I'm only going to be in here for a moment. I'll make it up to him with a little gift."

Starlight's horn glowed, and the bit glowed and levitated. Then it vanished in a flash, and Spike's room filled with a mountain of gold coins. Somehow, he was too engrossed in the comic book to notice.

"Well, that definitely breaks symmetry," said Sunburst. "It can't be our universe because it would violate simple conservation of mass. There's no way you pulled enough energy from the mana field to create that much mass in our own universe."

Twilight sighed. "I guess that's that," she said. Then she gasped and planted a hoof over her face. "Oh, nuts! We can't rely on the spell as a spying tool anymore—breaking symmetry means it will slowly diverge from our universe!"

"Well, isn't that what we wanted?" asked Starlight. "Now we can't use it to peep on anypony in our own universe. Not legitimately, at least."

"Huh. I guess it's not all bad," said Twilight, and then she grinned. "It kind of frees us up to do scientific research without worrying so much. We can examine anywhere in the universe we want!"

"This is going to be the most amazing weekend ever!" said Sunburst, clopping his hooves in place on the floor. "It's too bad it doesn't go back in time further—I'd really love to use it for history. But everything else is still incredible."

In the viewport, Spike threw his comic book aside and gawked at the mound of coins. "Twilight?" he called out.

"The audio on this thing is kind of light," said Sunburst.

"There is no audio," said Starlight.

Twilight blinked a few times. "Oh no. That's impossible, isn't it?"

Spike burst in through the library door. "Twilight! Somepony just turned my room into a hoard. Is that your pile of bits?" he asked. "Because if it isn't, I'm totally going to get a large tub of rocky road with rubies."

"This doesn't make any sense. I can't have possibly cast the spell into our own universe," said Starlight.

Spike studied the projection screen. "Twilight, why is there a camera in my room?" he asked, his brow furrowed in displeasure.

"I told you this was an invasion of privacy, Star," said Twilight. "We're sorry, Spike. Yes, the gold is... it's ours. I'll put it in the treasury but you can have ten bits as a gift."

Spike beamed for a moment. "Uh, you're going to take the camera out of my room, right?"

Starlight moved the camera out of Spike's room and down the hallway, then into the darkness of the library's event horizon.

"Oh, it's a spell. Well, keep it out of my bedroom, please."

"We will," said Twilight.

"What a mystery! It can't be a simulation of our own universe," said Sunburst. "A way to produce as much gold as we want? It's impossible! What other explanation is possibly left?"

"I guess there's no broken symmetry after all," said Starlight. "It's still an accurate view of our own universe, even though it's just a simulation. But the free gold is still impossible."

"No broken symmetry... oh Celestia no." Twilight fell backwards into a sitting position on the floor.

"Twilight? I know that look... horsefeathers. What did we do?" asked Starlight.

Twilight grimaced. "Put the pieces together," she whispered. "We couldn't have cast the spell that made those bits, so who did?"

Starlight's mouth dropped open.

"Ladies? I'm not following," said Sunburst.

"I'm definitely not following," said Spike. "I'm probably going to need a refresher on what's been going on."

"Sunburst, Spike... The mana crystal is a simulation of our universe, which is running its own simulation of the universe, and so on. The reason the bits appeared in Spike's room..."

"Oh geez," said Sunburst, taking a deep gulp of air. "It means we're in one of the simulations!"