A Solid Choice in Abstraction.
It was another beautiful day in Ponyville. The sun was shining, the birds were singing, and Rarity was squinting into the unrelenting glare of Twilight's new castle. She couldn't put her hoof on it, perhaps because the morning light was attempting to burn its way through her eyeballs, but something about Twilight's castle seemed different. She spotted Rainbow flying by, or perhaps it was an afterimage seared into her vision, but she flagged it down anyway.
"Heya Rares, what's happening?" Rainbow swept in with a stylish dive, pulling in alongside Rarity with a casual flip of her mane.
"Rainbow, darling, does anything seem... different to you about Twilight's castle." She glanced towards the crystal monstrosity once again, wincing against the light. "I swear something seems different about it."
"Nope!" Rainbow took one glance and shrugged. "Still big, still crystal, still a tree."
"Ah, very well." Rarity shook her head and shrugged. "It must simply be my imagination. By the way, when will you help me with that new pegasus lineup? You know spring has the loveliest weather and I'm feeling positively inspired!"
"Oh, yeah, you know, I really gotta... with the thing. Fluttershy. Weather. Yeah." Before Rarity could so much as protest, Rainbow was a distant speck disappearing into the sky.
"She never does change, does she?" Rarity shook her head and took another glance at the crystal castle. "I swear something seems different..."
Within her castle, Twilight Sparkle was having a good day. A very good day. A wonderful day, even. All around her were triangles. Glorious, glorious triangles.
"Spike! Guess how much I've improved the structural integrity of the castle just by shifting is molecular lattice?" She practically bounced in place, her immensely stable triangular chair refusing to tip, with its wide base and balanced form.
"I don't know, Twilight, how much?" Spike sighed, scooping his triangular spoon through his triangular bowl of now inaccurately named Hay-o's.
"Over one hundred and twelve point three percent!" Twilight practically squealed, her triangle cut mane bobbing with excitement. "Oh this is fantastic! Now, if I could just figure out a way to replace spheres with triangles, truly the world would be perfect!"
"I'm sure it would." Spike mumbled, quietly contemplating how long it would be before he was forced to send Celestia a letter. It didn't help that his handwriting had become inexplicably more tri-angular ever since Twilight's little crusade had begun.
"Still, something to mull on another time. For now, I've Ponyville to deal with!" She hopped up, Spike perking up in alarm.
"Wait, Ponyville? Twilight, are you sure that's such a good idea?" He glanced around at the now rather egregious surplus of triangle motifs around him. "I mean, you might be princess, but it's not like you own all the houses."
"Nonsense! I'll just pass a decree that only triangles are structurally sound for building! Then I'll just be bringing Ponyville up to a higher safety standard." She grinned and pranced out the door, her triangular teeth looking unnervingly sharky as she plotted the renovation of her hometown.
"Uh, okay. Sure." As she bounced out to begin her latest project, Spike quietly edged the other way, mentally mapping out just where the quills and parchment were kept.
Celestia arrived to find Ponyville in chaos. Sure enough, just as Spike had warned, Ponyville was being overrun by triangles. Buildings lurched to one side or the other as their frames had been warped to accommodate a more triangular aesthetic. Cobblestones marched along in tessellated mosaics, and bridge railings zigzagged in repeating patterns. And everywhere was that same three sided design.
"Princess Celestia!" It took the princess a moment to recognize Rarity, as she now looked more like a piece of abstract art than a pony. Her entire form was now composed of triangles, which was honestly on some level slightly aesthetically pleasing. "You have to stop her! Look at what she did to my feminine curves! My curves princess, my beautiful curves!"
"I dunno!" Pinkie Pie chirped from her garbage can turned teleportation gateway. "I think it looks rather sharp! Hehe! Get it? sharp?"
"Yes, Pinkie, I most certainly... get it." Celestia sighed, rubbing her head. She'd hoped Twilight had outgrown her geometry phase with the 'trapezoid incident,' but clearly there was more work to be done. Steeling herself, she ventured into the angular wasteland before her.
It wasn't long before she found Twilight, sitting upon her throne of incredibly structurally sound construction. "Ah! Celestia! Fantastic! I have the most wonderful idea for the sun!"
"Enough, Twilight! You cannot simply mandate what shapes the world takes! There is a place and reason for every form in our world, and you must respect that." For a moment, Celestia dared hope as Twilight recoiled in shock.
"B-but, Celestia! You have to understand! No shape is better than the triangle! Even the circle is but a paltry second!" She waved her hooves around her. "Look at what I've done! Never again will this village fall to the odd rampaging beast or natural disaster! I have made it all better!"
"That isn't your call to make." Celestia declared firmly.
"Fine." Twilight's sharp, angular eyes narrowed. "I'll just have to prove it!" Her horn flashed, and a bolt of zigzagging energy ripped at Celestia, only to shatter against a golden shield.
"You've gone mad with power!" Celestia replied with a blast of her own, and Twilight leaped out of the way, her throne weathering the blast easily with its superior load bearing properties.
"No, I've gone sane with power!" She cackled wildly. "You're the one who's mad, thinking you can defeat me, and my triangles!"
"It's not a matter of if I can," Celestia bit out, teleporting above Twilight, her hooves poised to crush the smaller alicorn. "It's a matter of that I must!"
"Petty non-euclidian mentality!" Twilgiht's horn blazed, and dozens of jagged stone triangles popped up around her, forcing Celestia to break off or be impaled. "Behold my power! You're no match for my geometric superiority!"
"Which is why she isn't alone!" Twilight barely had time to turn before a bolt of lightning punted her across the room and into a particularly jagged section of wall.
"Thank you, Luna," Celestia panted, being helped to her hooves. "You were right, she wasn't ready."
"No, it is you who are not ready, for my revolution of trinity!" Twilight burst from her crater, wreathed in a bubble formed of interlocking triangles. "Behold my ultimate defense, and offense!" Running towards them, she rolled her shield mightily across the ground like some hamster ball of doom.
"Sister, together!" Joining their horns, the royal sisters combined their powers to drive Twilight back, only for their joined assaults to wash off the impenetrable geometries of Twilight's shield.
"Her triangle powers are too strong!" Luna wailed, her own blasts faltering alongside her sister's.
"Hold fast, sister! Her triangles may be strong, but our hearts are stronger!" She poured everything she could into the beam, briefly slowing Twilight to a stop.
"Hah! Your hearts are but pathetic curves!" Twilight pushed harder, once again overcoming their beams. "Mine is glorious triangles!"
The next day, Ponyville awoke to another brilliant morning, the flawless equilateral angles of the sun shining down blissfully on the beautifully tessellated land of Equestria.
Quietly, in Canterlot, Celestia and Luna finished erecting a stained glass window in honor of the newly crowned Princess Trilight Sparkle.
"Stupid invincible triangles," Luna muttered.
