Not that it's not complex enough, but that it's not simple enough.

Lin Xian recalled… the super artificial intelligence, VV, in the third dreamscape had said the same thing.

Back then, he couldn't figure out the "Mirror Puzzle" left by Huang Que (Oriole), so he consulted VV.

VV rarely thought for a long time.

Even the lights of the entire Rhine Sky City dimmed a bit, making Lin Xian feel instinctively that something big was coming, something really big was coming.

But as it turned out…

The answer VV finally came up with was unusually simple, even overly straightforward—

"I think… it means exactly what it says, you should look in the mirror more."

At that time, Lin Xian barely restrained the urge to tear apart a trash can.

He decided to ignore this artificial idiot.

But he didn't expect that.

Today, this line taken from a certain science fiction novel was spoken by Chu Anqing again, making Lin Xian feel a little dazed.

He suddenly thought…

What if?

Whether in this world or in history, things like being too clever for one's own good, or not seeing the obvious, often happen.

Moreover.

Chu Anqing wasn't an untrustworthy outsider.

She had not only passed Huang Que's strict selection;

She had also risked her life to go to the United States alone to cheer him on;

She had even argued with her parents to get the chance to accompany him into space to capture space-time particles;

Her father, Chu Shanhe, was a great hero who served the country and the people, and had helped him a lot in the fight against the Seven Deadly Sins;

All things considered…

Chu Anqing was, on the contrary, the most trustworthy person.

"Okay."

Lin Xian nodded:

"It's just that the question I've been thinking about is a bit mystical, and there are too many assumptions, so it might be a little difficult to understand. Let me put it simply, I hope… you can understand."

Chu Anqing was on high alert.

She sat up straight.

Her hands were placed neatly on her knees, like a good child in kindergarten, ready to listen to the truth of how many pears apples plus oranges equal.

After sorting out his thoughts, Lin Xian slowly opened his mouth:

"After watching movies like *The Matrix*, *Source Code*, and *The Truman Show* with similar 'brain in a vat', 'being in a real studio' settings, I often wonder, what method can be used to realize the falseness of the world?"

"The concept of 'brain in a vat' is equivalent to the enemy making you unconscious, controlling your brain, and directly inputting all kinds of information into your brain with a computer, including sight, hearing, smell, taste, touch, and the sense of existence and movement of the body. This way, as far as your brain is concerned, it's like being in a colorful, incredibly real world that's no different from everyday life."

"But in reality, no matter how real your brain thinks this world is, it's still fake, fabricated by a computer; there will be an evil doctor who controls everything you see, making you his experimental subject, or simply laughing at you."

"As for the concept of a studio, you must understand it, after all, you've seen the movie *The Truman Show*. It's that when you wake up, you find residents, cars, shopping malls, cinemas… everything in everyday life around you. It's just that these are all actors and props arranged by the director. The huge studio is as big as several cities, and hidden cameras are all over the place. If you don't travel far by plane or train, you'll never realize that you're the protagonist of a reality show, your private life is being broadcast 24 hours a day for the whole world to laugh at."

"Let's assume that I, you, or anyone can be in such a brain in a vat, a studio as big as several cities, and incredibly real. Then, under the premise of being completely monitored and controlled by the enemy and the director, what methods do we have to make ourselves aware that we are in a fake world?"

"Of course, it's not necessarily to prove that these virtual worlds are fake, you can also try to prove that they are real. Positive proof and negative proof are both acceptable. If there is a way to prove that the world you are in is real, that is obviously more reassuring. In short, we must come up with a way to give us, who are trapped and confused, a clear answer—"

"[Is this world real, or is it fake, virtual, a built-up studio?]"

……

Lin Xian finished his long speech.

Chu Anqing was stunned, her head already starting to smoke:

"I… I can understand the situation you're talking about. After all, there are many movies on the market that tell similar stories, so I have a concept in my mind about the situation you're assuming. In the movie *The Truman Show*, the reason why the protagonist was able to discover that the world he was in was fake was ultimately because the production team made a mistake, allowing the protagonist to discover the flaws, which led to suspicion."

"Listening to your description, if we exclude the possibility of the director or the enemy making mistakes, then I really can't think of any way to crack it for a while. After all… isn't there a poem that says, 'We fail to see the true face of Mount Lu, because we are in the mountain ourselves.' If you keep standing in Mount Lu, you will naturally never be able to see its full picture, just like you said about being in a fake world… being in a fake world, how can you prove the falseness?"

Lin Xian nodded and continued, "The director and the enemy aren't completely without mistakes either, let's assume one more thing. There is a [safe], this can be considered the only hope left to us under the negligence of the director and the enemy. You can put an item or a small note in it in the known reality; then you can still find this safe in that suspected virtual world. You can open it with a password and see what's stored inside."

"This is the only prop you can use, and it's also the only channel for material exchange and information exchange with the real world. So, if you want to find a way to prove the truth and falsity of the world you're in, you can only focus on this safe."

Chu Anqing suddenly understood, and raised her head to speak!

"But…" Lin Xian smiled and interrupted her, "I know what you want to say, it must be to have a friend put something in the safe that I don't even know, and then I set a password that no one else knows, and then I go there to open it and confirm the items inside with my friend, and then I can tell the truth and falsity of that world."

"However, don't panic, this question is far from that simple, otherwise I wouldn't be so troubled and thought about it for so long without getting any feasible answer. Because in addition to the previous assumptions, there is an additional restriction—"

"[The enemy or the director has plenty of time to crack the safe before you wake up, whether it's brute force or violent cracking, in short, they have the ability to know what's in the safe before you.]"

"[They will copy an identical safe and also copy an identical copy of the things hidden inside. Then, they will put this fake safe next to you who has just woken up, don't forget our previous assumptions… all props are enough to be mistaken for the real thing, just by sight, we can definitely not tell the difference between the safe and the objects hidden inside.]"

……

At this point.

Lin Xian finished telling the complete question.

And Chu Anqing's brain…

Was almost cooked.

This, this is the world of smart people!

Her roasted brain protested:

Why do these smart people torture their brains?

Why give themselves such a difficult question?

Is it just to sprinkle some chili powder to make it taste better?

"This…"

Chu Anqing blinked quickly, reached out and scratched her head, frowning and thinking for a while.

Then.

She shook her head quickly.

Brainstorm! Brainstorm! Brainstorm!

Boom!

"Ah…"

She sighed helplessly, rubbing her hands through her hair. Her deep brown hair, which had been smooth and neat just now, was now a mess.

And…

She accidentally wrapped a few strands of hair around her finger, and accidentally pulled it out when scratching her head, hurting Chu Anqing to cry out.

She looked at the hair wrapped around her finger, took it off, and threw it into the nearby trash can:

"Sorry, Senior Lin Xian, I seem to have overestimated myself."

Chu Anqing smiled embarrassedly:

"I'm going back to debate with my dad! It seems that the famous saying in that science fiction book is not a 100% correct truth. You said, a difficult problem that is so complicated just by reading it out, no matter how you think about it, it is impossible to think of it simply… If you encounter this problem in a logic test, it will take several minutes just to read the question."

"However, I just thought that if you really can only use the safe to connect the real and suspected fake worlds, since the enemy and the director can open the safe in advance, know what's inside, and copy it. Then, you must not put ordinary things inside, such as souvenirs, handicrafts, toys, stones, or dolls…"

"After all, the enemy and the director can 100% accurately copy these things, so putting these straightforward things is meaningless. I think the idea you just said is good, the only way to deceive the enemy and convey hidden information—"

"[Is a small note with words written on it.]"

"It's just… I can't think of what to write on the note for a while, so that the enemy and the director won't see it in advance, copy it in advance, and make it look real? I understand, Senior Lin Xian, this is the reason why you've been frowning all this time, right? You're also so troubled because you can't think of what to write on the note, right?"

Lin Xian nodded.

In fact, that was indeed the case.

The foundation and association of words are far beyond imagination.

Sometimes in a novel, a seemingly ordinary sentence, even a few words, two words, one word… can make readers burst into tears.

Is this the power of those few words?

No.

It's those few words, the story behind them.

Lin Xian believes that the meaning behind the words, the small note, and the content…

Is the only hope that can break through 600 years of time and space, break through the enemy's surveillance, break through all the barriers of reality and falsehood, and allow him to instantly realize the truth.

"Senior Lin Xian, I'm sorry to disappoint you."

Chu Anqing raised her head and looked at Lin Xian:

"But… I really thank you for being willing to tell me these things and share your troubles with me. As your good friend, I will definitely find a way to help you and think of a way for you!"

"Although I'm not that smart, three cobblers are as good as one Zhuge Liang! Hehe, don't worry, I won't tell anyone about these things you've told me. In the future, when I'm free, before going to bed, when I'm taking a shower, I will think about this question. Someday… I think I will come up with an answer!"

"Of course~ Maybe by the time I come up with an answer, Senior Lin Xian, you must have already thought of the answer! Let's think together! Let's solve this problem as soon as possible!"

Lin Xian smiled slightly.

He used a fork to pick up the last small piece of birthday cake and put it in his mouth.

It was a little sweet.

But it was still delicious.

Brain thinking always requires a lot of sugar, so it was excusable to put so many spoons of sugar in this cake.

……

"Thank you for celebrating my birthday."

After finishing the cake, Lin Xian and Chu Anqing cleaned up the table and the trash together. Lin Xian thanked her:

"I'll prepare a gift for you on your birthday."

"Hee hee, that's great!"

Chu Anqing's face was full of joy, she threw the last bunch of trash into the trash can, clapped her hands and smiled:

"Do you still remember what date my birthday is, Senior?"

Lin Xian smiled without saying a word:

"Of course."

After all, there was an acting maniac who rapped in his ear every day, and it had already formed a mental imprint.

Lin Xian picked up the plastic bag from the trash can, tied a knot, held it in his hand and looked at Chu Anqing:

"It's getting late, we have training tomorrow, let's go back and rest early."

"Yeah, yeah."

The two walked towards the training room corridor.

*Click.*

Lin Xian turned off the light switch.

The entire training room was pitch black.

In Chu Anqing and Lin Xian's eyes, the dim white light in the corridor ahead was reflected. They chatted and laughed, one on the left and one on the right, walking from the darkness into the light, their bodies bathed in light.

In this laughing corridor, Lin Xian officially walked towards his 25th birthday.

*Bang.*

The dormitory door closed, and the fingerprint lock automatically locked.

Lin Xian walked into the dormitory carrying a bag of trash, staring at the electronic alarm clock that was pretending to show the time:

"VV."

He snorted softly:

"You must have discovered that Chu Anqing was making a cake in the kitchen, so you kept acting crazy and yelling, not letting me sleep, right?"

*Whoosh~~~~Whoosh~~~~~*

The time displayed on the electronic alarm clock turned into =3=, and it even made a whistling sound as if it didn't hear anything.

"You heartless thing."

Lin Xian laughed:

"You can rap Chu Anqing's birthday in my ear eight hundred times a day, but you didn't even say happy birthday to me. But I'm fine, you said I wouldn't think it's cheesy enough, and besides, not many boys like to celebrate their birthdays. Not many people remember my birthday normally, I didn't celebrate my birthday last year either, Gao Yang forgot my birthday, and I forgot his birthday a long time ago."

"But… VV, you clearly know Zhao Yingjun's birthday, why didn't you remind me? Although I finally set off fireworks for her at Disney, it was still too late, you could have reminded me."

"What's Zhao Yingjun's birthday?" VV asked.

"January 15th," Lin Xian blurted out.

"Hehe."

The electronic alarm clock VV smiled:

"See, you clearly remember it very clearly. Birthdays are like this… People who really care won't forget, and don't need others to remind them."

"Don't try to explain it, you just didn't want to remind me."

"What I said is true," VV said with a smile, "In order not to disturb Chu Anqing from celebrating your birthday, when you left this dormitory, I put your phone on silent mode, and also turned off all App message push notifications."

"Can you put this kind of consideration on Kevin Walker?"

Lin Xian complained:

"Can you do something that a super artificial intelligence should really do? Send a missile to Kevin Walker, blow up his refrigerator and microwave, and short-circuit his computer or something?"

"Are you an artificial intelligence or a phone butler? In the future, I don't need you to put the phone on silent mode or turn on do not disturb mode, I can handle it myself."

Saying that, Lin Xian picked up his phone, ready to turn the silent mode back on—

Huh?

There was a small red dot in the upper right corner of the WeChat icon, indicating that there was an unread message.

Lin Xian opened WeChat.

There were two messages sent 40 minutes ago.

Just right, it was March 20, 2024, 00:00

[Zhao Yingjun: Happy birthday, Lin Xian. I won't have a chance to send you a gift this year, let's make it up together next year.]

[Zhao Yingjun: Although I don't know what secret mission you're on, but… I wish you all the best and success.]

……

Lin Xian put down his phone and looked at VV.

People who really care won't forget, and don't need others to remind them.

So.

That's what it meant…

"You're so dog, VV."

Then, he squatted down, put the bag of trash he was holding on the ground, untied it, and started rummaging through it.

"What are you doing, Lin Xian?"

The electronic alarm clock VV widened its eyes again:

"Why are you digging through the trash?"

"Did you forget?" Lin Xian said while rummaging through the trash, "Didn't we agree before that after this mission to capture space-time particles is completed, we would go to Qufu, Shandong, to dig up Zhang Yuqian's grave, and then find the remaining DNA… and compare it with Chu Anqing's?"

Lin Xian pinched a few strands of hair from the trash bag with his right hand.

He held it in front of his eyes.

Deep brown, slightly curly, shiny and smooth.

He smiled slightly:

"Chu Anqing's hair… I got it."