Work Header

Twilight's Test

Work Text:

"Consider your answer carefully, my faithful student," Princess Celestia said gravely. Well, it might not have been so grave as all that, but, to the young Unicorn hanging on her mentor's every word, nothing could be more serious. The warm light filtering through the tree they sat under, the smell of the flowers in the Royal Gardens, and the normally-irritating whine of insects faded almost to nothing as Twilight locked her attention onto the Alicorn. She could feel the great, weighty machinery of her intellect revving up as she anticipated the Princess's challenge, and didn't feel the unconscious half-smile growing on her face.

"The scenario is this:" Celestia continued, "an accident at the nearby weather factory causes unscheduled and pervasive downpours over a large farming community. As the Pegasi are busy dealing with the factory itself, the burden of resolving this situation falls on the local Earth Pony population, as well as the very small number of Unicorns living among them who can contribute little in the way of powerful magical aid. While the community is wealthy enough and well enough supplied with stores of food that this situation will not affect its overall health, latent Pegasus magic present in the rain causes an increased chance of severe colds among anypony working hard outside--a farmer tending her fields will have a one in five chance of contracting a cold every day she's exposed to the elements, and the cold's debilitating effects last for several weeks, but are not contagious."

Twilight nodded absently for her to go on, already finishing her first page of notes. With her head down, she didn't see the Princess's fond smile, and even if she had wouldn't have noticed the twinkle of mischief in her eye.

"Putting aside the possibility of outside intervention, and assuming that the unnatural deluge continues for an extended but unspecified amount of time, what should the farmers do?"

Twilight's brow furrowed as she scanned over her notes, and she presented her mentor with her usual series of rapid-fire followup questions, inquiring as to the exact size of the population, the number of Earth Ponies versus Unicorns, the average family sizes and number of workers per family, and the areas, locations, and compositions of the crop fields. Celestia provided answers, to the sound of more furious scribbling. "And--" Twilight began, before she was smoothly interrupted. "Yes, Twilight, you can also assume that no 'outside' intervention means No 'Divine' Intervention.", Celestia clarified, putting a hoof to her own chest.

"These things sure got a lot harder after you started tacking NDI Clauses onto all of them." Twilight grumbled. After getting the last details on the Pegasus magic present in the rain, Twilight declared herself ready and levitated her notes into her discarded saddlebags, lifting them in turn onto her back, as she turned to head towards the Royal Library. "I'll need a few days for research, of course--farming isn't exactly my area of expertise. Well, it isn't yet."

Celestia waved a hoof at her departing student. "Take as much time as you need, Twilight Sparkle. I look forward to your answer with great interest!"

Dusty Shelves had been head librarian of the Royal Library for many years, and she knew well by now the glint in Twilight Sparkle's eye that meant that the special, engraved, Princess-granted library card, with its prodigious lending limit, was about to be maxed out. She smoothly reached over to a bell on her desk and carefully sounded a chime, another chime, and then two in rapid succession. Librarian ponies across the library felt their ears twitch upright and their eyes widen involuntarily at the sound.

Two Weeks Later

"It's done! Hahahaha! It's DONE! This will change Equestria... FOREVER!"

Spike was not around to hear Twilight's triumphant cry. He wasn't even in her Canterlot apartment anymore--just hanging around the city, taking some time to himself, y'know? Definitely not hiding. Would never have run away to sulk after the last reaction Twilight'd had when he'd interrupted her by trying to bring her food. He was totally chill!

Twilight's mane was a snarl and a tangle that even Pinkie Pie would have considered a bit unruly, but her papers were in perfect, perfect order. She divided the sheaves of her thesis precisely into two piles, and levitated them into her saddlebags. When the small panniers proved inadequate to contain the mass of papers, she very calmly hurled them to the other side of her room, hunted down her larger traveling pair, and fit the papers into those. Her hooves brushed against several plates of long-cold breakfasts and dinners as she scuffled around the room, and she favored them with a haughty glance. She didn't need food. Her stomach had stopped grumbling ages ago, and now seemed to have filled itself with the hard, cold light of academic achievement. She glanced habitually at herself in the mirror on her way out, froze, and slooowly rotated the mirror to face the wall. Anxious, she checked the time out her window--just past sunrise.

She'd need to see Celestia right away to take advantage of her precious few personal hours before the Day Court began. Nothing for it, then. The Princess, she decided smugly, was not like other ponies--who cared what she looked like--anyway. The Princess cared most about what she thought, and what her mind could do. Thus emboldened, she set out at a trot for the Palace.

Celestia sat watching the sunrise, and, as Twilight approached, spoke without turning around: an enigmatic mannerism of the sort immortals can afford. "My faithful student, I hope you are also enjoying what I must say is a particularly fine morning. Fortunately for us, it is enhanced by no raincloud. How fare our theoretical farmers?"

"Oh, Princess!" Twilight enthused, hurrying forward as her mentor turned to face her. "They fare well! Perhaps even better than you could have imagined!" Some might have cocked an eyebrow at this, but, knowing her student, Celestia's face was calm and interested.

"Okay." Twilight cleared her throat, "Since the Dawn Of Time--No, sorry. That's an older version of the introduction, hold on. Okay. Ahem. The first problem to be resolved is the effect of the rain on the farmers' crops. Fortunately, Pegasus magic dissipates almost immediately upon contact with earth, so the cold-carrying magic won't get into the crops, but the rain itself will cause them to suffer if it continues too long, and flooding could also be a danger. What if they had different crops? These days farmers use the standard three-crop rotation cycle, with fields lying fallow for short periods in between rotations. However, my research in Heavy Hoof's An Historie of Equestrian Agriculture found that about two hundred years ago, a four-crop rotation cycle was the norm, with thirstier crops grown during the rainy season! Historically, the advances in weather control magic caused more predictable rain, and the spread of the railways made growing certain crops for export more profitable, leading to our current system. For these farmers, however, a concerted effort to replant their fields with new--or should I say, old--rain-loving crops could result in an eventual but significant reduction in the loss of overall yield! As far as flooding goes, I've designed a new, hopefully more efficient, flood-resistant irrigation system that should help channel the excess water relatively harmlessly. Fluid dynamics being what they are, this part wasn't exactly easy to test, and I'd need more time to do a full study, but... it's the best I can do for now."

She looked up nervously, several diagrams and maps floating in her telekinetic field, and the Princess nodded for her to continue.

"The next problem is the farmers getting sick. Obviously they need to go out into the rain to work, and it's not like they can just carry umbrellas or wear heavy raincoats while doing farm labor! These would only be half-measures in any case, as the chance of some rain getting through and causing illness would still be inadvisably high. My first breakthrough was when I started thinking about Pegasi, and how they stay dry themselves. Of course their passive magic takes care of most of it, but they also have oil glands under their wings that they use to preen their feathers, keeping them orderly and waterproof."

Twilight broke off as she cast a subtle glance at the Princess's folded wings. Did she...? It didn't seem polite to ask.

"Ahem. If Pegasus magic can keep ponies waterproof, maybe Unicorn magic can reproduce the effect! I didn't forget that you stipulated only a small Unicorn population, so it would need to be a very simple spell--or, better yet, an artificial oil, in potion form, that could be distributed without having to continually recast the spell on each farmpony! Naturally I began my research with Starswirl's Stupendous Slippery Surface, but that's battlefield-level combat magic, and at four alliterative concatenations that's a spell I'd be a little nervous about trying for the first time--the IFF component is both tricky and crucial, after all! Fortunately my spell won't need to Identify Friend from Foe, so I can drop that runephrase entirely, as well as most of the area-effect clauses and all the casting-time reductions."

She demonstrated, making a floating diagram of fiendishly complex interlocking circles and runes orbiting around each other, and gradually paring it down to a single central circle with a few runes inside it.

"With the rest of the spell removed, what we have here is, basically, Slippery. I won't presume to improve on Starswirl's elegant work here, so I just added a runephrase to filter rainwater specifically, with a subclause in it for Pegasus magic, and a duration-enhancement to make it last." She demonstrated this change, and a line appeared connecting the central circle to another, smaller one, containing the runes for her additons to the spell.

"Best of all, we can easily make a pony-applicable potion with locally-sourced ingredients--given the demographic and regional information you provided--and the Slippery spell is simple enough to perform that any Unicorn capable of two Thaums or above can imbue the potion with it, in bulk quantities! The only tricky ingredient is the distillation of lantern oil and powdered chicken teeth, but that's such a small component that a gram of it can make a dozen gallons of potion. With that, it should be possible to mass-produce and distribute, making the farmers immune to the rain and the magical colds! And there's even more--"

Celestia politely raised a hoof to forestall her student. "One moment, Twilight." The Princess cast a critical eye over the list of reagents for the potion, and walked closer to the floating runes for Twilight's spell, examining them from several angles. Spellcraft was a notoriously difficult field, hence the reliance on centuries-old mages for their contributions, and she had to admit that Twilight's simple, almost minimalistic spell proved her more of an artist than the young Unicorn probably realized. "This is excellent work, Twilight! The potion, however, has a small flaw."

Seeing Twilight's face fall, she hastened to elaborate. "Show this potion recipe to your friend Zecora, and I doubt she could improve greatly on its efficacy, but I think she'd remind you of the words of the ancient Zebrican sage Ehomba, who, upon receiving the final potion of his most prized student, said:

'Of a finer-brewed potion I could not tell
but ask yourself: how will it taste and smell?'"

Twilight's ears flopped in embarrassment, and Celestia felt an answering pang of empathy from across the centuries--what Twilight didn't need to know, after all, was that the Princess of the Sun had once been that prize student. "Potioncraft and the culinary arts have much more in common than is immediately apparent, and--I imagine this potion was to be applied directly to the coat?"

Twilight looked miserable. "Actually... given the ease of producing a bulk quantity, I was going to recommend total immersion in it, to ensure no rainwater got through. Since the amount of Pegasus magic needed to cause a cold wasn't specified, I thought it'd be safest... but I didn't even consider how it would... smell..." Imagining, she shuddered.

Celestia patted her comfortingly with a wing, softening the blow. "Don't fret, Twilight. You didn't have the time or material to prototype a sample, and would have figured the scent issue out on your own, well, right away. All I've done is save you a single experiment. I think if you substitute alfalfa here and river water here you should end up with a rather pleasant odor, actually!"

Twilight beamed with pride. Although it was rare, having her mentor actually collaborate with her on a project meant Celestia was very excited about it indeed. "That's great, Princess! All my other improvements rely on these formulae, so I welcome any refinements to them!" The Princess's voice was curious. "Other improvements? Didn't you already solve the rainfall and sickness problems?"

Twilight gave an airy wave of the hoof she didn't realize she was borrowing from Rarity. "Of course, but that only took me five days! After that I started thinking about my modified Slippery spell more, wondering if it had other practical applications. If we're using it on the farmers, maybe it could work on their equipment, as well! Specifically, I started thinking about applying it to their plows. Wood and metal can't get sick, so we can relax the strength of the water-repellent enchantment a little, since it doesn't matter as much if a few drops get through. And..."

Celestia nodded in understanding. "Clover's Third Law."

"The strength of a magical field is inversely proportional to its duration." Twilight quoted, reflexively. "Right! This means I can shrink the size of the secondary circle, simplifying the spell even more, thereby extending how long it lasts!" She demonstrated. The spell consisted of a circle containing the Slippery component in runes, which was connected by a line to a smaller circle with the waterproofing runes, both of which orbited around their mutual axis, the line. As Twilight shrank the second circle, the orbit started to wobble slightly. "Now, this simplification throws off the stability of the spell, but..." she added a new line, opposite the first, and created an empty third circle at the end of it, the same size as the secondary one. The spell's orbit shifted so both outer circles rotated serenely around the center one.

"Symmetry. Very good! All the longest-lasting spells make use of it." Celestia smiled. "What were you planning on using for the tertiary component of the spell?"

Twilight was aglow with barely-repressed excitement. "It's a fascinating question, isn't it? What spell component is simple enough that anypony could cast it, but still useful given the other constraints of the spell, and weak enough that it won't overbalance the whole thing? Then it hit me: what's the first spell any young Unicorn learns? Hover Object!"

The third circle filled in with a single, simple rune.

"Of course," Twilight continued, "when scaled down to this size, it's really more like Lightweight than Hover. Which is actually ideal for our purposes--after all, we don't want to hook ponies to plows that go flying off into the sky!" the slight unhingedness of her laugh betrayed her recent lack of proper sleep. "I'm thinking of calling this version of the spell Tilling Timesaver."

She scuffed a hoof "It...It doesn't really have... any of those flamboyant extra counterbalancing circles like Starswirl's spellcraft, or the beautiful fractal nesting like Clover's. There's not enough of a signature, enough style, to call it Twilight's."

Celestia's opinion on the matter differed, but she kept it to herself, for now. Her student went on, excited again. "Anyway! With such a stable orbit, we can cast this spell directly onto the plow as an enchantment, no potions required, and it should last for months, if not years!"

Celestia seemed about to say something, but Twilight plowed on. "And what that means, is that if we can anticipate this spell will be cast on a plow in advance of its construction, we can use different wood, change the shape of the blade, in fact, we can do nothing less than achieve the dream of every engineer for the last three thousand years: we can redesign the Equestrian Heavy Plow! Just look!"

With a triumphant flourish of her horn, Twilight displayed a new spread of papers from her thesis, this time showing detailed schematics for her design. Celestia leaned close and examined them with interest. "This is a very elegant design, Twilight! It looks frail, but there's strength in just the right places. It looks almost... Deerish."

Twilight nodded rapidly, almost vibrating with excitement. "You noticed! There's a sketch of one of their abandoned Temple Trees in North Star's Journeys Across Equestria, and I've always been fascinated by it, since I was a little filly! The curve here is almost exactly copied from the Temple archway, and--you see the way the plowblade itself curves, here and here? I based it on some of their ceremonial weaponry found at the Chital excavation site! In collaboration with the spell's Lightweight component it reduces overall weight significantly, while actually allowing more surface area to contact the ground, and since the Slippery component of the spell effects it as well, it should be much easier to pull! And the best part is..."

Twilight was literally jumping up and down now. "Oh Princess, Applejack told me once about how excited and how proud she felt the first day she was finally strong enough to pull the Heavy Plow like her big brother, how she worked all day until the sun set, and didn't want to ever take it off--of course, it is really heavy, so she did eventually, but still! Combined with Tilling Timesaver, my new plow design is so lightweight and so easy to use that fillies and colts can start pulling it at full efficiency years earlier than they can pull the modern Heavy Plow! To think that all those farmponies could have years more productive work to contribute to their families--the way they'll feel, not to mention what it will do for the community-wide crop yields and overall productivity... let me show you the graphs!"

She showed Celestia the graphs.

There were a lot of them. They started out sketchy and speculative, and gradually became more precise and defined. The last few were almost frighteningly detailed, lines with hundreds of data points surrounded by their defining equations. "Given the family demographics you set as parameters, and a conservative estimate that my design lets fillies start working two to three years earlier than normal, the corresponding increase in the workforce puts the Average Productive Workers Per Family from one point seven up to three point five!" She beamed with triumph. "Okay." She took a deep breath, and let it out slowly. "Let me show you the simulation."

Twilight levitated up the last few pages of her thesis, which contained a long, quill-written spell meant for verbal invocation. Twilight spent a few minutes carefully, precisely pronouncing each arcane syllable before her horn flared to life. From the lavender light it produced, a little holographic town was displayed on the grass. Simulated farmponies toiled in the fields under the pouring simulated rain, with the raindrops bouncing off of them harmlessly. Twilight leaned over to whisper, "the drops won't actually bounce off--at least I don't think they will--but I couldn't think of a better way to display the effect at this scale." Celestia gave a conspiratorial nod.

The two watched as tiny unicorns came out to enchant the plows of the farmponies, which suddenly zipped along, more easily planting the new crops, and the PRODUCTIVITY and CROP YIELD numbers to the side of the simulation rose accordingly. Gradually, artisans replaced the old Heavy Plows with Twilight's Deer-inspired plow, and suddenly the fields were full of ponies working, digging new irrigation, and even expanding the land under cultivation. The FOOD STORAGE and OVERALL TOWN WEALTH numbers began to stabilize, then to rise. Twilight waved a hoof to advance the timeline, showing that eventually the village would become very prosperous indeed despite the initial weather factory accident, assuming the eventual return of normal weather patterns.

Celestia politely stamped her hooves in applause. "This is very well done, Twilight! Quite comprehensive. I'm also impressed by this spell you're using to display it in the first place. May I see it?" Twilight gestured, and the Princess took hold of the scroll with her magic and brought it up to examine. Then Twilight groaned aloud as she saw the old familiar look in Celestia's eye--the one that meant she was missing something important. "While I am truly pleased with what you've accomplished in so short a time, my faithful student, I have two major points of contention with your work. One is a series of variables you've miscalculated, and related to it is an entirely different answer to my question that you've so far left unexamined. Let's start with the former, and see if you can figure out the latter."

Twilight sighed in resignation, by now used to accepting the Princess's--always constructive--criticism. "I'm ready."

"To begin, when you thought about farmponies, their work ethic, personalities, and capabilities, I assume you naturally began with your memories of your friends in the Apple clan?" Twilight nodded. "Well, Twilight, to put it honestly, the main flaw in your calculations is that not every farmpony is Applejack." Twilight blinked. "To elaborate, not everypony is a Rodeo Champion, an Iron Pony contender, and a Running Of The Leaves finalist. In fact, I think even I know of only one pony with the unique combination of grit, endurance, and stubbornness that lets her refuse all help and attempt to harvest an entire orchard by herself! Remember, Twilight, not every pony born on a farm has the inclination, much less the Special Talent, for farming. Can you think of a good example of this among your other close friends?"

Twilight thought for a moment, then smacked her forehead with a hoof. "Of course! Pinkie Pie was born on a rock farm, but she was miserable there! Wow... she might be even more unhappy in my little rain-drenched farmworld." She poked a hoof tenderly at one of the tiny hologram ponies, as if to comfort it.

"An astute observation, Twilight," Celestia continued. "When estimating the reactions of a large group of ponies, it is wisest to assume a great variation in their dispositions. One pony might run away from danger, another towards it. It's important to remember that both of these are perfectly valid reactions: I have seen many promising young ponies run from danger and survive, and many run towards it, never to return... This is not to say that ponies should not be brave, but rather that to act bravely, like anything else, is a choice each pony must make for herself." Shaking off the shadows of the past, she went on.

"When considering your farm population, imagine that there will be a few Applejackish ponies who are at their happiest when performing hard, predictable, solitary work, and a few PinkiePieish ponies, who need spontaneity, variety, and socialization. Other ponies will fall all along this scale, and there may be other kinds of outliers--ponies who refuse or are unable to work, ponies who leave the community, ponies with Special Talents for Gemcutting, or Bioethics, or Hats. In this scenario, it is in the ponies' best interest to work their farms, but it takes hard work both to replant and irrigate fields and to implement your very clever improvements, and the rewards of that work won't come for what these ponies will think of as a long time." Twilight nodded her understanding as her mentor continued.

"Keep in mind that ponies are not always perfectly rational and predictable: they may even act against their own interest, or that of their community, for reasons that, from the outside, from the perspective of a..." Celestia did not say Princess, and she definitely did not say Goddess, "a... historian, are somewhat mystifying." She shrugged a wing. "Though I may have seen more of ponies than any other living being has--save, perhaps, for my dear sister, that is--they still surprise me, almost constantly." Though the Princess's eyes were distant, her smile was fond.

Twilight sat, in the peaceful garden, watching the regal Alicorn remember.

After a while, the moment passed. "Have you thought any more," Celestia asked, "about the different possible answer to my question, 'what do the farmers do?'"

Twilight dismissed the simulation spell in order to improve her concentration, and closed her eyes in thought. If there's another answer to this question--one that doesn't involve, for example, a revolutionary redesign of existing Earth Pony agricultural technology using a fusion of long-lost ancient Deerish design and cutting-edge theoretical Unicorn spellcraft, It's not one I'd think of, but perhaps...


Twilight imagined herself in a farmhouse. The Apple Family farmhouse. The feel of the floorboards, the smell of the air... Applejack popped into existence in her mind's eye, complete with hat. She addressed the Applejack, feeling a little silly addressing a literal figment of her imagination, and told it--her?--the problem the Princess had posed. Applejack scratched the brim of her hat.

Then she took her hat off and scratched her head.

Then she put her hat back on.

"Wellll, as near as I can figure it, there's really only two different things a pony can do in that sort of a predicament. And well, you know our Apple Family--there's that old Mule saying, 'Stubborn as an Apple'--and we'd probably just take our chances out in the fields, magic or no, and try'n salvage something. We don't sicken too easy, anyhow." She nodded proudly to the framed crochet piece hanging on the wall, an old one of Granny Smith's, that bore a large red apple in the middle surrounded by the words



"I can't imagine most ponies'd be half so foolhardy as us, though, and as for your average farmpony... sometimes you just lose a harvest. And you move on. That's part of farmin' life, even for us. If they really did have enough bits and beans stored away to last 'em the duration, I guess they'd just--"


"--come in out of the rain!" Twilight blurted. "What? Is it really that simple!? Am I really that stupid!?" She boxed her hooves against the sides of her head repeatedly. "Could they really just... literally weather the storm!? Is this sort of thing where that expression COMES FROM? This... this is one of those tests where figuring out the parameters of the test is part of the test and I set my parameters too wide, I do that every time..."

A vision of her tombstone filled her mind's eye. "Here Lies Twilight Sparkle. Faithful Student. Beloved Friend. Element Of Magic. Died Alone. Too Dumb To Come In Out Of The Rain." A low, constant, whining-groaning noise filled her ears, and she realized she was making it. Suddenly she came back to herself, sitting on the grass, in the garden.

She couldn't see the Princess through the tangle of her hair, and, as she parted it and looked up, her stomach clenched as she had the sudden, awful thought that she'd see Celestia smirking down at her...

But the Princess's eyes were wide with concern, and she rushed forward, wrapping first one wing and then the other around Twilight's shoulders, staring seriously into her eyes. "Listen to me, Twilight Sparkle: You. Did. Not. Fail. My Faithful Student, we have long since passed the time for simple pass/fail quizzes, and as I said: there are merely two different answers to this question. One is multifaceted, forward-thinking, and theoretical. The other is simple, immediate, and practical. One of the many things you will hopefully take away from this assignment is the ability to consider both solutions simultaneously."

Removing her wings from Twilight and folding them, Celestia reached down with a hoof to tousle her student's snarled mane. "In life, sometimes you need to come in out of the rain. Sometimes, you need to revolutionize agricultural engineering. Sometimes a pony needs to give a simple answer to a question and spend her two-week vacation back to her hometown seeing the sights and visiting old friends. Sometimes," she said, grinning warmly, "a pony needs to remember what it's like to pull a few all-nighters working on a really tricky academic assignment. If I'd wanted somepony to give me the second answer first, Twilight, I would have asked another pony. Many ponies would have given me the simple, 'obvious' answer to the question--and they would not have been wrong!--but none of those ponies," she concluded, "are my Faithful Student."

Celestia's horn lit with her magic, and she pulled a well-laden picnic basket and a hairbrush from their hiding place in a nearby tree.

"Now! You need to clean yourself up, and eat something, in whatever order you prefer. It may please you to know that I'm currently mentally drafting a letter to the Equestrian Academy of Agricultural Engineering regarding your new plow design, and another to Professor Morning Glory, a recent acquisition of my College For Gifted Unicorns. I think she'll be very intrigued by the practical applications and the theoretical magery of Twilight's Tilling Timesaver," she held up a hoof, forestalling any protest about the name, "as she shares your, shall we say, rather adventurous approach to spellcraft."

Celestia finished laying out the picnic blanket and arranging the meal on it as she spoke.

The hairbrush lay forgotten on the grass as Twilight literally dove headfirst into the hayfries.