>You're fortunate the weather is good, because everypony involved insisted on conducting your experiment outdoors.
>Twilight had teleported it out of your workshop in pieces, but reconnecting everything wasn’t too difficult.
>A private garden for the princesses now hosts four individuals and one jury-rigged machine.
>Twilight stands at one end of the device, a metal shaft sticking out of it towards her.
>Celestia sits on a balcony on the other side of the machine from you, to intervene in case something goes catastrophically wrong.
>You stand near a hand-wheel that controls the transmission, in front of a big sliding bar that indicates the transmission’s current setting. A paddle with one red and one green side rests on top of a notepad on the control box.
>Behind you sits a guest you requested Twilight bring; a musician with absolute pitch.  The gray earth pony holds ready a cello, and a violin sits on a table beside her.
“Alright, first run is a dry run. We’re going to see how fast we can crank this thing, and establish some base values. We’ll put some weights on after to simulate loads.”
>You crank the hand-wheel until the sliding indicator is at one end of the bar, then give Twilight a thumbs up
>The shaft near her lights up with a magenta glow, and the machine starts turning
>A lone rubber flap at the far end of the machine starts slapping against a bar, once for every rotation. It picks up speed quickly as Twilight turns it faster, becoming a loud droning tone.
>You turn to look at the pony behind you.
“What are we hearing, Octavia?”
>She thinks for barely a moment. “E2”
>Now you just had to remember what frequency E2 was
“Uh, can you, uh… give me a G2 or something.”
>Octavia dutifully complies, bowing the cello’s second string with long, even strokes.
>You hold up your painted paddle with its green side facing Twilight
>She nods, then focuses on the shaft again. The drone starts slowly increasing in pitch.
>As the pitch gets closer to the note Octavia’s playing behind you, you turn the paddle to be more edge-on to Twilight. The drone’s increase in pitch slows down, and you can hear the moment they match.
>You turn the paddle edge-on. The drone’s increase slows to a crawl. You can hear a very slowly cycling pulse between the two, and start counting seconds in your head.
>When you count two pulses a second, you drop the paddle. Then you listen for a bit longer; this would be way easier if you could isolate yourself and listen to the two sounds alone, instead of dealing with echoes off the palace walls and the rattling of your thrown-together bearings.
>Satisfied, you draw your hand across your throat. Twilight stops the machine, and Octavia follows suit.
“Alright, that should have been about a hundred cycles a second. You were turning that bar far faster than that. Was the effort posing you any problems?”
>Twilight tilts her head in thought. “Not much, as long as I didn’t have to do it for a long time.”
>You make a few notes on your pad, then look back at her.
“Your speed control is remarkable. I didn’t think it’d work that well.”
>Twilight draws her head up and beams. Even Celestia’s smiling from her balcony perch.
“Alright, this time, just roll it as fast as possible. Go when you’re ready.”
>Twilight resumes right away, the drone quickly picking up speed. When it sounds like the pitch leveled out, you look back at Octavia.
>”D… Somewhere around D♯3”
>You do some quick math in your head. Then you flip  few pages back in your pad and look at some of your earlier calculations.
“Holy shit.”
>Twilight stands in a wide stance, staring at the spinning shaft like she wants to set fire to it with her mind, but she doesn’t look like she was about to fall over. There’s room to kick this up some more.
>You make another note on your pad, then grab the hand-wheel controlling your transmission. Slowly, you start cranking it.
>The drone starts increasing again, slowly at first, and then faster as you continue to crank.
>When you look up at Twilight, she’s staring back at you in alarm, chest heaving.
>You stop cranking the wheel and give her the stop signal. No use wearing her out so soon.
“How high’d we get, Octavia?”
>”Around D4, Anon.” She shifts her cello in her grip, then looks to her violin. “Will you want me to play over it?”
“Uh, yeah, why don’t you get ready for that.”
>While Octavia switches instruments, you make a quick note on your pad, then jog over to where Twilight’s catching her breath. Squatting down next to her, you look her over real quick.
>What are you even looking for? Damnit, you’re an engineer, not a veterinarian.
“Hey, sorry about that. Still don’t really know how the whole magic thing works.”
>”I’m… I’m fine. Did I ruin… your data?” She already looks a lot better, but is still panting.
“Only if you slowed down before I told you to stop.”
>She shakes her head no.
“Then we’re all good.”
>You look up to Celestia’s balcony. She's standing at its edge now, eyeing the two of you with an unreadable expression.
“Is she going to kill me if you collapse down here? Because we only found one end of your upper bound, we still have a whole curve to define.”
>”She’s just concerned, Anon. But next time… Warn me before you push me that hard.”
“Yeah, sure. Well I mean, this is your warning then. I want to see if magic is biased how it can be used to deliver power most efficiently. I had you spinning this thing as fast as possible, then started changing our gear ratio. Next step is working at the opposite extreme. Don’t worry, I wont be able to make it more difficult this time.”
>”You know, Anon," Twilight gives you a weary smile. "Usually I’m the one taking notes.”
“I promise I’ll share.”
>You reach out and tousle her mane just behind her horn as you stand and turn back to your post. You don’t even realize it until you stop; these pint-sized ponies are too precious for you sometimes. They’re like giant puppies, who’d be able to resist?
>Octavia’s giving you a weird look. She apparently doesn’t feel it important enough to actually tell you why, when you’re back at the control wheel.
>You look to your purple assistant again as you start cranking the wheel as far as you can.
>Twilight and Celestia are sharing some wordless communique by eye contact.
>You guess the Princess was just concerned for her after all.
“Whenever you’re ready, Twilight. As fast as you can.”
>Now the sliding indicator bar is pegged on the opposite side it started at.
>After taking about a minute to compose herself, Twilight faces the shaft again. Her eyes bulge in shock when she first tries to move it, but she leans into it, and gets it spinning again in short order.
>The droning sound of the smacking rubber flap very quickly escalates.
>Once it evens out, you back at Octavia.
“What are we at now?”
>You wonder if she can hear the pitch over the awful rattling of your crappy bearings. You’ll have to think of another solution.
>”Almost A4.”
>After making a few more notes, you grab your colored paddle, and show Twilight the green side.
>Then you start cranking back on the hand-wheel.
>The drone drops in pitch, at first, but quickly recovers. You stop your turning every once in awhile to pencil a line on the sliding bar and take notes, asking Octavia for the different pitches she hears.
>Eventually you’re back near the range you snuck up on Twilight the first time. You give her the stop signal.
“Alright, that was good. Lots of good data. Now lets put some weight on this and see what changes. If you could-”
>Disk-shaped weights – pilfered from a gym somewhere in the guards’ barracks – on the opposite end of the machine from Twilight start levitating, but are illuminated by a golden rather than magenta glow. They deftly slot themselves onto the shaft at that end.
>You look up at the balcony and give Celestia a thumbs up.
“Thanks. Uh, keep an eye on them, please, Princess. We don’t exactly have them secured in-place. If they start coming off, just sorta nudge them back again.”
>Celestia dips her head, in a gesture you’re not sure is a deep nod or a shallow bow.
“Alright Twilight, I’ll be going back up again. Try to keep it spinning as fast as you can; when it gets too heavy, just back off until it’s manageable.”
>Twilight nods and resumes her work immediately.
>You work your way back across the range again, taking more notes as you continue changing the ratios. Every so often you have Octavia play a note, and try to get Twilight to match it.
>Near the top of the range, you notice a larger dropoff than you’d expect.
>Twilight’s squeezing her eyes shut, standing in the same splayed stance from earlier. Her horn’s almost touching the rapidly-spinning shaft. Celestia’s looking back and forth between her and the weights, but you doubt Celestia’s seen what happens when bodies touch hardware spinning at those speeds. You have. Safety videos aren’t supposed to give you nightmares, but someone, somewhere, didn’t get that memo.
>This damn thing doesn’t have an emergency stop.
>You drop your notepad and hit a dead sprint in three strides.
>The palace tailor’s going to have to make something more mobile for you than this damn suit they insisted on copying from what you wore when you arrived.
>When you reach her side, you brace one hand against the machine’s frame, and place your other hand square on her chest, shoving her away as hard as you could. She stumbles and falls, and the shaft stops glowing.
>Celestia’s already over the balcony railing, gliding down to where you kneel, a look of great concern on her face.
“Before you ask, yes, I had to.”
>You tap the end of the now almost stopped shaft.
“She got too close. You don’t want to touch these things when they’re spinning that fast. This is just a pretty smooth bar, there’s not a lot to get snagged on, but I’m not going to trust that. If that weird magic aura’s able to interact with objects, I didn’t want to take the chance her horn would latch on and snap her neck before you even had the time to realize what was happening, let alone do something about it.”
>Celestia looms over your still-kneeling form. “It sounds like your technology carries some great risks.” Despite her intimidating presence, she speaks in a worried tone.
“There’s a reason I wanted to keep everything in the workshop. Once I have constant power, I don’t want some pony frying themselves or something. When the final generator’s built we can include all the safety features. I just… wasn’t thinking about that for this one-off design, especially when the final product will be much smaller.”
>Twilight finally gets to her feet next to you. “You could have just said stop, Anon.”
“I didn’t know if you’d hear me; you were flagging. I think we’ve done enough experimentation for one day.”
>The two – three; Octavia’s put her instruments down and stands near your controls and dropped notepad – ponies watch you as you stand and inspect the machine. You check the rubber flap near the weights. The thing’s absolutely shot. How it lasted this long you don’t quite understand.
“I don’t think we could have gotten much more out of it anyway.”
>You return to Twilight and Celestia. They didn’t appreciate that close call, you felt. Maybe you really were jumping at shadows. But if you overstated the risk, Celestia may demand you stop your work.
“I’m sorry, Princess, for dragging you out here. I’m sure you have better things to do with your time. Twilight, thank you for your help. You were great. I’ll send you everything I have once I’ve made a copy.”
>The two look at each other, and then back to you. Twilight cracks a smile. “Despite the abrupt end, if you got good information, the effort was worth it. I’d be happy to work with you again.” She looks back at Celestia, with the last few words.
>Celestia looks between you and Twilight several times, worry still plain on her face.
“She would make a great assistant.”
>Your mumble barely reaches her ears. After a few more moments, she flashes a resigned smile.
“I was wrong, Anon. It seems Twilight would be a good fit after all. But if you’re going to work with her, I insist on being more mindful of safety. If something were to happen to her – or to you – I would be quite cross.”
>Now it’s your turn to smile.
“Yeah, I’ll do that. Thanks.”
>”And,” Celestia says quickly, “I insist on being present, if you ever have to take work out of your shop again. If there are risks, I wish to know about them. It’s my job to know any threats to my ponies.”
“Yeah, of course.”
>”Now,” she says, looking over you two and Octavia.
>You stumble when the machine beside you suddenly blinks out of existence with a golden flash.
>“If we’re done here, how about some refreshments?”

* * *

>After recovering her strength, Twilight insisted on returning to the workshop with you.
>Said recovery involved eating enough food to last you a whole day.
>Some ‘snacktime’.
>Is magic bound to some sort of metabolic exertion? Might be worth investigating, but that’s one kind of mechanics you don’t really have the tools to measure.
>Either way, she is now fully reinvigorated. You suspect some sort of sugar-high; while you could normally outpace most ponies’ polite speeds with a power walk, Twilight was staying alongside you engaged in the bounciest trot you’d seen to date.
>”So it’s not a novel device, for us, though I’ve never seen one before that can assume any ratio at will. Ours have to be built with gears or cogs, this cone and wheel setup is fascinating, and so simple! Honestly I’m ashamed we hadn’t come up with something like it sooner.”
“Belts would probably be better, but I was being lazy.”
>You can’t help but smile at her enthusiasm.
>She’d grasped the concept as soon as you explained it, no schematics or math required.
>You liked working with these types, who could just think their way through a design.
>”How would belts work?”
“Wide and thick, triangular cross-section. Belt shouldn’t stretch when under load. Load side has two cones – straight this time – held together by a spring. Drive side has two cones with controlled spacing.”
>You hold up your hands, index fingers extended and pointing towards each other.
“Changing the spacing on one side will force the other to change inversely, since the belt has to keep the same length. Since the pulleys are cones, this means the belt rides on a narrower or wider cross-section. The difference in diameter of these cross-sections determines your ratio.”
>You bring your index fingers closer together and further apart. It looks kind of stupid, and you aren’t sure what it's supposed to demonstrate.
>At least it keeps your hands busy; Sugarhighlight was looking at them funny when they were just hanging at your side, close as they were to her body when she was trotting beside you.
>You can’t be too surprised that foreign anatomy might freak ponies out.
“We use them a lot at home, but I wouldn’t build one here for a final product, not when we’re concerned about reliability. I was thinking of  a magnetic one, but I couldn’t think of how to design one quickly. I’ll just crunch some math, get a fixed ratio, and make magnetic gears for that.”
>”What’s so special about magnets?”
“Even just the bearings I used there weren’t great. I’ll have to get some better ones, see who makes your trains around here. But I want this to be as reliable and low-maintenance as possible, and noise is also something of a concern. The more magnetic components we have, the less physical wear, and the less noise. Plus, they can slip freely and catch each other again, so we don’t have to worry about catastrophic failures from that angle. I want to see if they’ll work, first.”
>You rub your chin in thought.
“Come to think of it, magnetic bearings exist too. But there’s Earnshaw’s thorny problem, or I’d need a control system for electromagnets. Honestly, I keep running into problems I’d need control systems for, and that makes things more complicated.”
>Twilight tilts her wings in a remarkable approximation of a shrug. Has she been watching your body language?
>”Just use your mind.”
>You stop and stare at her.
>She trots around in a half-circle to face you. “What?”
“Did you just tell me to control an electrical balancing act with my brain?”
>She nods vigorously.
“I don’t have telekinesis like you do.”
>”I let a tortoise fly before, Anon. Using a bit more complicated version of the spell we’ve been talking about this whole time.”
>You resume walking, and she kicks back into her bouncy trot, this time on your other side.
“Did you give it wings or something?”
>”No, a rotor.”
>You look at her again, one brow quirked.
“Just one?”
>”Yep.”
“Nothing else?”
>”Nope.”
“How’d you provide antitorque?”
>”Compensated for it within the mast.”
>You don’t even know how that’d work.
“So you’re telling me your magic can provide control over at least two degrees of movement, alongside a speed control, while automatically balancing a resultant force?”
>”Well, Tank still needs to handle the torque. Just has the tools to do so.”
>Who names a tortoise Tank?
“Well, that opens up a whole bunch of options. But I’m not going to sit next to this generator and mind-control it into balance. If you have a spell that can just keep something centered or whatever, that’d be easier. Short of that, we’ll deal with the stuff you use for trains and shrink it down or something. I mean if we really have to I could just just reverse-engineer a locomotive’s drive components and have you spin a wheel instead of a shaft, but that’d be something far larger and more complex than I need. I would like my generator to fit under my work desk. I’m just one man, not a power station.”
>”Doesn’t that mean the thing you built is a bit large?”
“Was easier to work with larger parts. We have enough data I should be able to extrapolate in either direction. Besides, if you said you made a magical helicopter fit for a turtle, I don’t think down-scaling will be an issue.”
>”Tortoise, Anon.”
“Yeah, that.”
>You two reach your workshop. Your test rig is all there – Celestia teleported it in one piece this time, but still fit it with room to spare – and so is your notepad.
>But something nags at you. Something about what the two Princesses were saying, a couple days (nights?) ago.
>You’ve done enough math for today.
“You know what? Let’s walk and talk.”
>Twilight hesitates, but ultimately turns and follows you. “Weren’t we just doing that?”
“Yeah, well, Princess Celestia thinks I’m working too hard.”
>”But… science!” Despite the plaintive tone in her voice, Twilight still hasn’t lost the bounce in her gait. “There’s as much we can talk about! So much I can show you!”
“Calm down there Miss Sakamoto, I’ll go blind.”
>”So much about magical theory that could be helpful to your projects-”
“Yeah I’m sure it’s poetry in motion.”
>”That’s a beautiful way of looking at it.”
“Can’t take the credit. Look, all I’m trying to say is the Princess doesn’t really let me out of the castle, but she thinks I’m working myself to death. I’ve been here for months and my only respite from being a court showpiece is to do work for free that I used to be paid for. You’re here now. If we’re going to be working together, lets get to know each other a bit, huh? You can show me the town.”
>It's her turn to stop in her tracks, forcing you to hold up for her.
>”Really?”
>You shrug.
“Is there a problem with that?”
>”But Princess Celestia-”
“Wants me to get out more.”
>Twilight shakes her head and resumes her trot. You can her muttering to herself as she passes you. “...sheltered colt putting me on the spot after...”
>She’s still bouncing.
“So uh, so what do you normally do, anyway? Are you like head of the Royal Society here or something?”
>”Well, I do a lot!” Her cheerful tone’s returned. “Solving problems, helping friends, studying all SORTS of things.”
>You fall in behind her.
“None of that sounds like Princess stuff. Celestia and Luna are running the kingdom. Are you not heiress apparent?”
>”Don’t be silly. Celestia and Luna are immortal. I’m not related to them, if that’s what you mean. Just close.”
“Ah, sorry Princess, but that makes no sense to me.”
>”I found it a bit much to get used to myself. Please don’t feel a need to call me ‘Princess’.”
>The two of you make your way through the palace and out into a courtyard. Guards stare at you and Twilight as you head for the main gate, then into the city beyond. With Twilight here, at least they don’t try to stop you. It’s not like you're trying to sneak out anyway.
>Canterlot’s riotous architecture is even more vivid from the ground in the middle of it. The sheer amount of gold everywhere boggles your mind.  If you can duplicate materials at-will, why not go for the top, you figure.
>Away from all the nobility, you feel distinctly overdressed. Not just because you’re wearing a suit, even one that’s worse for earlier wear, but because you’re wearing clothing at all. Most ponies in the palace are adorned in some way or another, but Twilight’s birthday suit fashion has a lot of admirers, beyond the castle walls. You’ve seen it before, during petitions, but being surrounded by it is another story.
>The ponies you’re eyeing rarely return your gaze, but a couple stare at your feet.
>”Are you hungry?, I could take you somewhere nice.”
“Eh. From what I saw back there, I’m surprised you can even think of food.”
>Twilight sighs. “We can make it light and fast.”
“Celestia never gave me access to some royal bank account. I’m broke.”
>Twilight gives you a confused look. “I’m paying, silly.” She looks back ahead, then angles off towards a nearby cafe. “Your world must have been a strange place, Anon.”
“I can’t believe, with the reputation you have, you didn’t read my file.”
>”Oh, I did. Nine times, in fact. It just raised more questions than it answered.”
“Nine times?”
>”I had to be sure I got everything right, because so much of it made little sense. No magic whatsoever, but you somehow managed to go to the moon. Two hundred nations for one species. And don’t even get me started on the accounts of the device in your pocket.” She turns to you as she reaches the cafe’s door. “Think we can make one?”
“Twilight, the original doesn’t even work, I need to find a way to charge it. Uh, thanks.”
>You enter first, Twilight having opened the door before you could even reach for it.
>Twilight heads for a table for two – far from a window, you note – and telekinetically pulls out the chairs. She doesn’t sit down when you do, with your back to the shop’s front.
>”I’ll grab something I think you’ll like. Be right back.”
>You take some time to look around. The cafe is almost empty for this time of day, but its few occupants have definitely noticed you. Going incognito your first day out of the palace was never an option, but that doesn’t make their staring any more comfortable.
>When Twilight returns, she hovers to you a plate with a curious pastry on it. She has a different one for herself, and finally takes her seat.
>You take a bite.
>It tastes like a cross between a cinnamon bun and an apple cider doughnut.
>You need to find out if the palace kitchen makes anything like these.
>”Your file,” Twilight said, “included very few social or cultural details. I understand it wasn’t exactly an interrogation, but I thought you’d have volunteered more.”
>You shrug.
“I’m an engineer. My everyday interactions with the world were through the lens of science and technology. Go to work to help make it. Come home and entertain myself with it.”
>”You know a lot of what you told us was unbelievable, right?”
“One of the reasons I decided to try to show you instead. Most of it I won’t be able to, but I’ll be happy with a little slice. Your magic can make up some of the lost potential.”
>You take another bite of the pastry. Holy shit this tastes good.
>”I’m looking forward to it,” Twilight says, after swallowing her own bite. “I’m just curious, were men like you common? There’s few stallions interested in studying magic, and even fewer science, here.”
“Magic aside, most people like me were men.”
>Twilight’s eyes boggle. “Really?”
“Yeah, something like eighty to eighty-five percent. So when you say there’s few stallions you know into this stuff, trust me, the feeling’s mutual. I never knew a lot of, uh, mares.”
>Twilight stares down at her half-eaten pastry.
“Look, I get it’s rare. I’ve seen the traits Celestia selects for in her guards. I’m not going to pretend to understand. I’m not a pony. I’ll just go on working in my shop and feeling overdressed.”
>”Well, you could stand to lose the, ah, footwear.”
>You take another bite while you think on this. Definitely not in the shop, but outside? If fingers were weird enough, heaven forbid ponies get a gander at toes.
“Nah, the shoes stay on.”
>Twilight’s eyes dart to the entrance of the building briefly, before she speaks again. “You are a bit overdressed, besides that.”
“I have yet to convince the palace tailor to make me much else besides this crap. They insist on using the same pattern, no matter what I request. At least they fit better; I’d go insane if I had to wear a real suit for as long as I’ve been here.”
>”You could just go without.”
“Twilight, back home that’d get me arrested. And wouldn’t get me any closer to being warm.”
>”Arrested?” She sounded incredulous.
“Yeah. Indecent exposure or whatever.”
>”Indecent?!” Now she looks as incredulous as she sounds.
“Yep. No nudity in public. So forgive me if I want to keep some clothes on.”
>Twilight shakes her head while chewing another bite. When she’s finished, “Humans are so backwards.”
“Hell, in the winter, clearing snow, I’d wear three layers on top, and two pairs of pants. Tuck one pair’s legs into my boots. Thick socks, all the way up to my knees.”
>You have to suppress a laugh when she nearly chokes. She glances at the door again, then back to you.
“Just let me hold on to some habits from home. I already feel awkward enough.”
>She nods. “S-sorry.”
“Meh, I figured I’d need a big cultural exchange talk eventually.”
>”It would probably do you good to get out more.”
“As long as you’re around, sure. Trust me, I’d have this city memorized if Celestia would let me out on my own. I’m too weird for most of the court; nobody wants to be my chaperone, but Celestia insists I have one if I were to ever leave. Can’t have the great ape banging his head on a low door frame. Just means I’ve been stuck. Now that you can do that job, I have a chance. And seriously, I appreciate it. Thanks.”
>”Don’t mention it, Anon. I’m happy to.” She takes a third glance at the door. This time, you turn in your seat and follow her gaze.
>Despite your location in a rear corner of the establishment, the cafe is small, and you’re not quite isolated from all the windows. Pedestrian rubbernecking is causing minor traffic issues on the sidewalk outside.
“Like I’m some goddamned celebrity.”
>”You are. You being shut up in the palace hasn’t actually kept you a secret, not with Celestia showing you off inside it. It just fuels more speculation.”
“Maybe we should scram, before someone gets hurt. Twists an ankle, goes lame. Uh, there’s some things I’m never going to disclose about the long and storied relationship between humans and equines, by the way. Sorry to disappoint.”
>Is she blushing?
>”I know of a garden that might be a little more secluded. We could have a bit more privacy there.”
“Lead the way.”