1

Considering the battery capacity, only one miner's lamp and one tactical flashlight were used during the trio's march. At this time, because they confirmed that they had been walking for a long time, they were actually just going around in circles, and the three of them turned on all the miner's lights and flashlights.

"This is the last altar we went up to."

Xiao Yu said as he looked at the marks drawn on the stone.

"It stands to reason that we're only a few tens of meters here. But look around—"

Professor Cheng used a tactical flashlight to shine around, and no matter which direction, he couldn't see the entrance they had entered.

There are only altars of different heights and huge stone pillars that reach to the sky.

"Now, we seem to be in the center of this large altar. But there is no direct road to the front and left. So there's no way to know which direction is right. I think the most efficient way is for us to go our separate ......."

"No way!"

"No!"

Sajir and Xiaoyu opposed at the same time.

"Have you forgotten the coughing we heard when we first entered the corridor? There must be some danger in this that we haven't noticed. Therefore, the bottom line is that the three of us are not separated! Sagir said in a very anxious tone, for fear that Professor Cheng would insist on going his own way.

Professor Cheng looked at Xiao Yu.

"The association sent me to keep you safe. Can't be separated. Xiao Yu said firmly.

Professor Cheng sighed helplessly, then rummaged through his backpack and found a marker.

"This is a fluorescent marker, and from now on, we will number every altar and pillar we pass by. The numbers 1, 2, 3, and 4 are recorded past the altar, and the letters A, B, C, and D are recorded when they pass through the pillar...... I don't believe it, even the Mayan underground palace I can go in and out at will, such a small altar array can trap us? ”

2

So, the three of them set out again, this time using their memory to move forward in the opposite way as before, and constantly marking with fluorescent markers along the way. The fluorescent nature of this marker pen can last up to 100 hours in the dark. It's completely dark, so the signs are more visible.

In this way, although the speed is a little slower, they have become more confident in going out.

So, half an hour later, they returned to the place they had marked.

……

"Hell!" Professor Cheng sat down on the ground with some frustration.

"I didn't study the formations, but I played maze games for a while."

Sagil suddenly calmed down. He sat down next to Professor Cheng, took out a bottle of water, took a sip, handed it to Professor Cheng, and continued:

"Since junior high school, I've been obsessed with mazes for a few years. Every summer vacation, I go to those famous maze attractions to play, and I also download various maze games and buy many books related to mazes. I just thought, even if this is a formation, it's actually just a labyrinth. ”

"Well, that makes sense. You go on to say. Professor Cheng nodded.

"There are two main categories of plane mazes, that is, 2D mazes - single mazes and complex mazes. There is a one-size-fits-all approach to the single maze, which is as simple as touching the wall on the right with your right hand, which may take the longest time, or it may take you through every corner of the maze and every dead end, but you will never be trapped in it forever. ”

"There is no road here that is blocked, and it is certainly not a single maze. What about the Maze? ”

"There must be some places in the maze where you can walk back to the original point without looking back, and this passage that can be walked back to the original point shows a closed loop in the maze, and with this circuit as the boundary, the maze can be divided into several parts. Therefore, the complex maze is essentially composed of several single mazes. So, let's still follow the method of marking just now, but mark each loop. With the help of your tablet, draw a map as you go......"

"Have you ever wondered how much time this will take?" Professor Cheng said with some disappointment.

"We're just right, not in a hurry." Sagir said with a smile.

3

If you're not in the middle of it, it may be hard to understand why people can get lost in a space the size of a football field.

Let's try to get a feel for the actual situation.

First of all, the altars here divide the space into narrow paths. The lowest of these altars is also two meters high, which means that you can't see the path beyond the altar from the path, let alone the huge stone pillars that appear from time to time. Maybe you marked (1) on the east side of Altar 1, but when you turn around and you go back to the south side of Altar 1, you may have marked (7) in the order in which you encountered it, but (7) should actually be (1), which creates confusion. Under such confusion, people quickly become dizzy.

Sagir's method is very simple, the first altar encountered, on the four sides of this altar, each side of the left and right corners of a total of eight corners are marked with the serial number (1), and the first pillar encountered on the four sides and eight corners are also marked with the letter ā.

In this way, the kind of confusion mentioned above will not happen.

At the same time, after determining the position of the altar (1), the adjacent altar (2) is the altar, and then the altar (3) is marked...... By analogy, then a complete and accurate map can be drawn on Professor Cheng's tablet. According to the map and serial number, if you want to get out of this formation (maze), there is naturally no problem.

In theory, yes.

4

However, the actual implementation took far more time and physical strength than they imagined.

Professor Cheng brought two fluorescent markers with him, and by the time they reached Altar 84, they had run out of fluorescent paint.

"We've been deliberately going in one direction, it stands to reason that this 'altar square' can't be so big? I measured it with my steps just now, and the average size of these altars is only ten meters, and no matter how you look at it, this hall is only a few hundred meters. This...... Isn't that right? ”

Sagir looked at the altar in front of him, which seemed to have no end in sight, and muttered.

"Unless, unless, these altars are not squares, but trapezoidal or ......"

"Or a pentagon or even a hexagon." Xiao Yu frowned, looked gloomily at the road between the two altars, and said, "These roads are also wide at one end and narrow at the other. ”

"So we're still going around in circles, but this time it's bigger." Professor Cheng leaned his back against the altar, his body slowly slid and sat on the ground, and said very depressedly: "It's really breathless, it's better to come out directly and fight some kind of monster face-to-face!" ”

As if to verify her words, suddenly, at this time, behind them, there was a burst of "hey, hey, hey" laughter.

5

Sagil reached out and pulled the gun out of his belt.

As he pulled out his gun, Sagir felt a gust of wind pass by in front of him.

Looking up again, Xiao Yu was gone.

In the direction of the road they had just turned, there was a series of rapid collisions and striking.

At this time, Professor Cheng also pulled Sagir to stand up. She adjusted the mechanism of the miniature steel crossbow on her wrist, and ran with Sajir towards the location where the sound was coming from.

Turn the altar and the sound is gone.

"Xiao Yu! Xiaoyu? ”

Professor Cheng shouted a few times, and the voice echoed in the darkness, but there was no response.

The two of them circled around this altar again, and then turned around several adjacent altars again, and Xiao Yu seemed to disappear out of thin air.

"Xiao Yu! Xiao Yu ......"

Sagir also shouted loudly, still without a response.

They were back on the same path as before.

Thanks to the marks they had drawn earlier, they were able to make sure that they were not misplaced. The two of them carefully examined the road with a strong flashlight, and from the marks on the ground, it seemed that there were scratches from the small Yu sickle.

However, no matter what, Xiao Yu won't be taken away silently like this, right? After all, both of them have seen Xiao Yu's skills, and if even he is captured without resistance, Professor Cheng and Sagir together will not be the opponents who don't know anything.

"Let's make sure."

Professor Cheng took the lead in calming down: "No matter what we hear or see again, we can't let ourselves out of each other's sight." ”

"I agree."

Sajir replied with a swallow of saliva.

"What time is it?"

Professor Cheng asked suddenly.

Sagir frowned and said, "Since I entered here, the watch has not been accurate, and there is a problem with all the electronic devices. So I can't believe it at this time. But I guess we're here, why would it take seven or eight hours, right? ”

"Excessive exhaustion, physical exhaustion, judgment, control will be reduced. We can't panic now, let's rest—"

Professor Cheng looked around, and finally raised his head, looked at the altar next to him, and said, "You squat, I'll step on you up, and then pull you up." Let's go up there and rest. ”

6

The altar next to him is three meters high.

Professor Cheng stepped on Sagir's shoulder and climbed up. Then Sagir threw both of their backpacks up, ran a few steps by himself, jumped up and grabbed Professor Cheng's outstretched hand. With her help, I climbed up too.

When they stood on top of this altar and used tactical flashlights to shine around and observe, the two of them felt nervous at the same time.

I didn't feel anything down there just now, after all, the line of sight would be blocked by other altars at most ten meters. At this time, standing on it and looking around, I realized that at some point, a layer of cyan fog began to fill the entire "altar square"!

"This ...... This fog isn't poisonous, is it? Sagir grew more and more flustered.

Professor Cheng took out a small plastic clip from his bag, a bit like a card wallet. After opening it, he carefully turned a page out of it, removed the sealant, took out a damp white test strip, looked around, walked to the pillar where the corpse was tied, and stood on tiptoe to stick the test paper on the top of the pillar.

"Every 10 and 20 minutes, just look at this test strip. If it changes color, it means that the air is poisonous. ”

After Professor Cheng finished speaking, he observed the altar, then walked to the center, took out a sleeping bag from his bag, put it on the ground, and said to Sagir:

"I'll sleep for two hours, and you'll be on guard. Wake me up in two hours and put you to sleep. ”

After saying that, she pulled the zipper from the inside and went straight to sleep.

Sagir looked around uneasily for a while, then took a look at the white test strip on the pillar to make sure it hadn't changed color, and then sat down next to Professor Cheng.

There was silence all around, and even the sound of his own heartbeat could be heard clearly.

Faintly, there seemed to be a cry.