"So Sai, the million-times brainpower genius, is Ryusui's big brother?!" Chrome exclaimed.
"Well, with the years spent out of the stone, they're probably the same age now." you thought out loud.
"Still, is there a reason we weren't told that earlier?" Gen asked.
"Mh? Seems like a pointless factor to me." Ryu said. "I desire Sai Nanami for his first-rate talent, is that so wrong?"
"Definitely wrong!" Sai exclaimed (free to breathe now that Kohaku let him go). "I've always told you, I'm not a genius! And yet, since way back when, you've been making those wild claims!"

"Huh, that's weird." Chelsea tilted her head. "So you're not a freaky genius?"
"Exactly! It's a lie!"
"How hilarious!" she took his hand and shook it. "Still glad to have you as a regular ol' pal!"
"R-really?" he asked, touched.
"Couldn't have said it better myself." you walked up to him and offered your best smile. "Hi, I'm (Y/n). I didn't know Ryu had a brother. It's so nice to meet you Sai." you offered him your hand.
"Ryu?" he quickly glanced at his brother before shaking your hand with a shy smile. "It's...It's nice to meet you."
"What's 462471 times 910835?"
"...421234773285."
"Ah-ha! Got'cha!" you pointed at him.
"Wowsy!" Chelsea exclaimed. "You *are* a genius!"
"No I'm not! That was easy!"

"Haha~! Good one my dear!" Ryu told you before pointing at Sai. "You've been trying to deny your talents since you were four years old!"
"Mental math, is, pointless!" he pressed on his words. "A computer could do the same calculation in an instant! And given enough time, anyone in the world could perform ten-digits multiplication like me!"
'Uh, sure.' you thought. 'If I multiply those ten digits by one, and if you give me a few days and a bunch of paper.'
"No matter what you think, you can't hide your obvious talent for math and science! Which is why Nanami Corp., no, I desire your abilities above all!"
"I knew it!" Sai held his head in anguish. "They all wanted to put me to work! So I left Nanami Corp. and Ryusui, and fled all the way to a university in India! I'm no mathematician, I'm a programmer! All I want...is to coding!"
His gaze wandered towards the landscape, a stone world with no technology in site (yet). This seemed to break his heart, and he hung his head down.

"How... How long will it take to achieve a proper modern day computer in this stone world?"
"Semiconductors are hell y'know." Senku replied. "Well, even hell is manageable. At this point, they're impossible, outta the question." he thought for a moment. "At best? Five years, maybe ten."
Sai pursued his lip, his eyes growing teary.
"Why did you...even revived a guy like me?"
Your heart shattered at his words. Senku glanced at you, having heard that before, long ago, from you.
"Revived into a world without so much as a pocket calculator." he continued. "What can a programmer hope to achieve here?"

Ryu tried to convince him, but he wouldn't hear it. You all decided to go back to the ship for the day, now that your mission was completed and all. Sai was given a room and he hasn't come out yet. It worried you. And it showed apparently.
"Hahaha~! Worry not my dear (Y/n)!" Ryu patted your head as you were all eating dinner. "Sai's just being his usual self, but when push come to shove, he's quite capable!"
"The problem isn't that he can or can't do math," you sighed. "it's that he doesn't *want* to."
"He said he's not even that quick when it comes to calculations, but we saw it!"
"Math doesn't seem to be his thing," Chelsea said. "kinda feels bad for the guy."
You sighed again, your eyebrows furrowed.
"You okay there (Y/n)?" Chrome asked.
"I just...I get where he's coming from."
Gen giggled, knowing what you were talking about.
"Who would've thought. The two of you are in completely different fields of expertise."
"That doesn't matter in the least." Senku casually said. "As long as they share the same level of passion for their own science."

You both exchanged a look. François noticed and they stood up.
"Now, if you'll excuse me," they bowed with a hand on their chest. "I will be delivering Master Sai's dinner to his chamber." they looked at you. "Lady (Y/n), would you like to accompany me?"
"Huh?! C-Could it be?!" Chelsea exclaimed, shocked but also excited. "Does the cool and smooth François also have a thing for (Y/n)?!"
They just chuckled. You got why they gave you this offer, ignoring the young girl's theory (also because it was funny), you accepted the butler's offer and the two of you went to Sai's room. On the way, you picked up some paper and pencils. They knocked on the door and opened it. The young man was sitting on the edge of his bed, looking pretty depressed.
"Master Sai, here is your dinner. And, you have some company."
He looked up and saw you, his eyes widen slightly in surprise and he let out a little 'oh'. François excuse themselves and they left the room. There was a short moment of silence before you spoke.

"Are you feeling better?"
"Not at all."
You couldn't help but smile at his honesty.
"Five whole years until a working computer, maybe even ten? What am I supposed to do in the meantime?"
"...I understand how you feel." your gaze wandered. "I experienced something similar."
"R-really? Are you a programmer too?"
You smiled at him.
"I'm a musician."
He frowned, confused as to how those two things could compare. You walked up to him.

"I used to believe that my talent was valueless here in this stone world. And yet, you know what was one of the first things I did when I got revived?" you leaned closer to him. "I played music, using a blade of grass." you chuckled at the memory. "No matter how much I tried not to, I couldn't shake off the need to play. You know the feeling, right?"
Hesitantly, he nodded. You walked up to the trail of food, where a bunch of pencils were on.
"So, if you're wondering what to do before we get a working computer..." you picked up one and handed it to him. "Why not get a head start?"
For a moment, he just looked at you with a spark in his eyes. Eventually, he took it and stood up.
"You're right. Who says I can't code?" he walked up to the trail and picked another pencil. "Coding is all I can do!"
"Two hands...?" you mumbled.
He walked up to the wall with a determined look, but just as he raised his hands, he stopped and glanced back at you, flustered.
"Oh!" you laughed and waved a hand. "I'll leave you to it, have fun~."
"Th-thank you (Y/n)." he nodded with a shy smile.
"You're very welcome." you smiled before leaving the room, closing the door behind you.
'He's pretty adorable actually.'

When you came back to the dining table, everyone noticed your mood has lighten up.
"So?" Kohaku tilted her head. "Is he going to do math for us?"
"I don't know about that," you smiled. "but he will keep doing what he loves to do. And to me, that's amazing." your smile softened.
"This is nice and all." Senku casually said. "But if he keeps being a wimp, we'll have to find a new mathematician."
"He'll do it." Ryu nodded. "It's only a matter of time."
"If anything," you leaned closer to Senku. "can't we convince him to help us? You know, Kingdom of Science style?"
An evil looking smirk formed on his face. The fact that you suggested that to him made his heart jump with happiness. He began to cackle maniacally. His reaction made you chuckle.
'They're at it again.' Kohaku thought. 'Being both cute and creepy.'

.
The next morning, you all went to check up on Sai. You peeked inside and you all gagged when you saw that he has covered the walls and furnitures with numbers and letters, and he was still writing! With both hands! When he heard you he suddenly stopped and blushed.
"Aaah! No! Stop! Don't look!" he pressed his back on the wall and waved his arms around.
"Kinda too late for that." you smiled.
"Also, how can we not? It's everywhere man." Chrome frowned.
He gulped and calmed himself.
"You see... I was thinking, even if this world lacks computer... What I can do in the meantime is jot down some code for later. Y'know, get a head start."
He briefly glanced at you, your smile widen. Then, you looked around.

"What are you coding exactly?" you asked.
"Right, no one can really read any of this stuff." Senku responded for him. "This is code for..." he looked around for a little wide before his eyes widen. "Dragon Quest! The whole deal!"
"What?!" you exclaimed, as shocked and as delighted as him, memories of your time in the modern world flowing back. "Seriously?!"
"You're telling us," Ryu walked up to him. "no matter how primitive the machine, your coding can create a whole universe inside a computer?"
"Indeed. It can." he nodded with a serious face. "That's what coding's all about."
"Kukuku!" you all looked at Senku. "In that case, change of plans! Sai, with your superior skills, we can wage this war with an old throwback computer. If you can make a NES, you can make a rocket fly." he smirked. "It's humanity's tech singularity! The ultimate apex of scientific crafting! That's right, the Kingdom of Science is getting a computer!"

At his words, while everyone expressed their shock, both you and Sai had stars in your eyes, your cheeks dusted with pink.
"Sai!" you turned towards him.
"Y-yes?!"
"Once we get a working computer, let's work together to recreate video games!" you looked into his eyes with determination. "I'll remake the entire Dragon Quest OST, maybe even make it better than the original!"
"A-all of it?! You can do that?!"
"Of course I can!" you flexed one of your arms with a big smile. "I'm this world's music expert, soon-to-be master!"
Your determination and support touched him. He nodded with the same look on his face.
"Yes! We'll combine our two fields together! As soon as we get a computer..." he trailed off before looking at Senku. "How exactly?!"
"Haha! Don't fret Sai!" Ryu said. "You're the one with a burning desire for a computer, along with (Y/n), am I wrong?"
"I mean, yes but... How?!"

"An excellent question, if I do say so myself." Gen said. "What are we using to make what exactly? I'm feeling lost before we even begun."
"You're always lost dude." you lightly nudged him.
"Computers are all about on/off switches." Senku explained. "It's a world of ones and zeros. Basically find a way to process those ones and zeros and you've got what it takes to make a computer!" he picked his ear. "Think of it like the front and back of a training card, or a flag that's either raised or lowered."
"Cards and flags give us a computer?!"
"I'm still not understanding." Gen and Suika were confused to say the least.

"I get the flag part but..." you tilted your head with a slight frown.
"You do (Y/n)-chan?!" they both turned to you.
"Yeah, back in the day, I once asked him what the deal was with computers and he made me do that test with the flags."
"Kukuku~! Of course you remember." Senku smirked as he stepped out of the room, with you following him not far behind. "Just as I expected from my girlfriend."
"Wha-?!" you blushed intensely and leaned closer to him, whispering sharply. "Is this gonna be a daily thing?!"
"If it is, you better start getting used to it." he looked at you.

You sighed, despite being caught off guard again, you were beyond happy everytime you heard him say it. Curious, the people in the room started to follow you guys, but some were too shocked to move.
"Girlfriend...?" Sai pointed at Senku. "She's with *him*?!"
Gen chuckled.
"I get it Sai-chan, I also thought these two were a complete mismatch." his expression softened. "But then I realized, it's only at first glance."

You all went outside, where houses were starting to be built. Senku gave a small red flag to Suika and a big red flag to Kohaku, and he gave two small white flags to Chrome and Gen. He then traced four squares on the floor and asked each of them to stand in one, the two duos facing each-other. This whole thing was to simulate how a computer works.
"The boys' flags represent the numbers, and the girls' flags represent our answer." he explained. "A raised flag is a one, a lowered one is a zero. Here's your job Suika. Watch the guys' flags and if one or the other is raised, you raise yours."
"Really? That's so simple." she said.
"And me? What do I do?" Kohaku asked.
"You raised yours when both flags are raised."
"Hah! This is the basic principle behind all computing!" Ryu snapped his fingers. "Let's test it out with some basic addition!"
"Addition?! Already?!" Gen exclaimed.
"It's literally one plus one!" you laughed. "Are you *that* bad at math?!"

The quartet went at it for a while without any errors, Kohaku looked very focused on her task like her life depended on it. Her expression made you snicker.
"They aced the test!" Chelsea cheered.
"That was all kinda obvious though..." Chrome mumbled.
"Well yeah, this is like the basics of basics, the real deal must be a hundred times more complex than that, right?" you looked at Senku.
"Right." he nodded. "The thing that produces those obvious answers perfectly is called a circuit."
Sai however, wasn't impressed.
"It's a simple half-adder." he said. "Easy enough to create with just a xor gate and an and gate."
"...what?" you said under your breath.
"And now we're back to words I don't know."
"It's fine Kohaku-chan. Even 21th century people such as us are utterly lost." Gen smiled nervously.

"But it's pointless!" Sai exclaimed. "Unless it's happening rapidly and electronically! You said we're a decade away from semi-conductors right? Without those, how can we craft a stone world computer?!"
"We're cooking up some donuts." Senku smirked.
"What?!" everyone asked.
Instead of giving an answer right away, in true Senku fashion, he asked Kaseki to make a little donut-shaped metal thing, made from copper and zinc, and then to coil a wire around the whole thing. The whole process took less than half-an-hour. This was Kaseki after all.
"For a brief moment in history, Japan used sheer ingenuity to compete, via this donut-shaped computer. The parametron!" he showed the final result to everyone. "And this is its basic component!"
"So quick!" everyone was shocked.

"L-let me guess!" Gen said. "We need about 800 of those?"
"For now, only five."
"That's it?!" your eyes widen.
"Yep! The way it works is to simple, you wouldn't believe it! Think of it as an electrical swing: the electrical oscillations are like a swing, moving back and forth. On a real swing, if you have some people swinging one way, and some the other way, the majority wins out and decides which way it moves. That's the defining trait of the parametron!"
"Do I have this right?" Suika's eyes narrowed. "The zappy electricity...is sort of swinging back and forth?"
"S-sure!" Chrome smiled. "The actual baaad science is still kinda confusing but, when you add a one, the output goes up by one, right? That's how it's capable of basic addition!"

.
Senku and Kaseki worked together to make an adder circuit, using indeed only five of those donut thingies. When it was done, Sai stared at it in wonder.
"Would you mind...if I try it out?" he asked.
"Heh, mind?" Senku raised an eyebrow. "When it comes to tinkering with computers, you're the team leader Sai."
He walked up to the device. It had two switches and two lightbulbs, one small, one big. Just like with the flags in your simulation, when just one switch was flipped, the small lightbulb turned on, and when they were both flipped, only the big one lit up. A collective 'woaaaah~' resonated throughout your group.

"Hah!" Kohaku just smiled. "Even without this computer thing, I could've told you that 0+1=1 and 1+1=2."
"Are you kidding me?! This is huge!" you pointed at it.
"Right," Sai said. "By creating more parametron adder circuit and linking them together, then, little by little, they'll be able to handle bigger and bigger computations. Until..." he sniffed as tears rolled down his face. "Our computer surpasses what we as humans can do."
You smiled and patted his back.
"Alright," he wiped his eyes, now more determined than ever. "let's get building! This right here is the first step towards my beloved computer!"
"Well, we're not gonna build this ourselves." Senku smiled. "We have a whole team on the other side of the world for that!"

So you guys contacted the people in North America to tell them about your new science project, and about their new task: make a bunch of these donut thingies! Even with just morse code, you could feel Yuzuriha's nervousness from here. And you knew everyone gagged when Senku told them to make and combine 200,000 of these.
"We'll create machinery that pumps out more metal donuts," he said. "plunging us into the age of automation! But the hard labor of coiling the wire is up to Yuzuriha and the handicraft corps up there. Keep reviving loads of folks to populate Corn City, and throw your new labor force at this task." he paused. "The computer is the apex of humanity's crafting, and making one is gonna take both machines and manual labor. We've all got a part to play if we wanna pull this off." he smiled. "Are you up for the challenge?"
There was a moment of silence before you got a response.
"You bet we are!"

Now, just because her team will do the heavy lifting, that doesn't mean you guys wouldn't work too. You all made a bunch math donuts yourselves and combined them together to make a bigger more complex adder circuit. You all cheered at the fruit of your labor so far.
"Haha! Fantastic!" Ryu snapped his fingers. "Now let's pump out Dragon Quest! Impossible you say?!"
"No one said that," you laughed. "but it's true that we can't do that just yet."
"Then how about a simpler game, like chess?!"
"Getting waaaay ahead of yourself." Senku smiled. "This computer's only level one."

"You guys are way too happy." Kohaku glanced at you guys.
"You're the one who's not happy enough!" you pointed at her. "Look at how much progress we made in such little time!"
"We can add up to 255 now." Sai said with the biggest smile of his face.
"And it's just a matter of time before we get a full on computer!" you raised your hand for a high-five. "And we *will* pump out Dragon Quest!"
Sai felt his heart skip a beat. He nodded and high-five you.
"Let's do this!"