A figure came from a distance, An Xiaoyu tightened the cottage gun in his hand, and walked in the same direction as the person. According to the alien race, their patrols are overlapping, and this kind of patrol is a way that humans can perform perfectly, but aliens are not necessarily.

The so-called overlapping is nothing more than a patrol area divided into two halves, for example, the first patrol area is called one, and the end point is divided into two parts, one before and one after. To the left and right of the patrol area of the first section, the patrol area of the second section and the patrol area of the twenty-eighth section are respectively, and these two sections of the area are also divided into two halves of the front and rear of the second and twenty-eighth and twenty-eighth.

The way of overlapping is that the patrol area represented by the 28th and the first front is the same, and the area represented by the first rear and the second front is the same. And so on, the second and third front overlap, and the third rear and four front overlap...... Until the twenty-seventh and twenty-eighth overlaps.

In order to ensure that the two adjacent teams can meet each other, the entire circle can be divided into two layers, the outer layer is the odd patrol area and the odd patrol team, and the inner layer is the even patrol area and the even patrol team overlapping with the outer patrol area.

Teams in the odd patrol area follow a clockwise direction, starting at the beginning of the first half of each area and walking back to the end of the second half. Then the team in the even-numbered patrol area patrols in a counterclockwise direction, starting from the end of the second half, walking towards the front half, and then walking back again.

When the first patrol departed, all the teams set off at the same time. When the first patrol team reaches the fourth minute point in the first front, it can meet the 28th patrol team that also departs to the second quarter of the 28th, and continue to walk forward, passing through the center point to the first and fourth quarters, and then encountering the second patrol team that has reached the first quarter of the second quarter.

This ensures that all parts of an entire circular area can be inspected by two teams, preventing an anomaly that is never discovered by one team unless it is discovered.

Of course, the division of each patrol area must also be scientifically planned, and it is determined according to objective factors such as manpower, weapon range, environmental conditions, and terrain, so as to ensure that at least after the two teams meet, each section of the area they walk through can be in the sight of any other team.

For example, after the 1st Patrol and the 28th Patrol meet at the first equinox, they should be able to see each other until they reach the midpoint of Area 1 and Area 28. After reaching the midpoint, continue to make sure that the first and second teams see each other, and the twenty-eighth and twenty-seventh teams see each other.

It can ensure that all teams can be supervised by other teams, and it is easy to control the agreed time to ensure that patrols are carried out correctly.

However, according to normal speaking, although this kind of patrol method is convenient and practical, and can reduce the boredom of patrolling, it requires good military quality and accurate time control to achieve it. Because the best way to achieve the best effect is that each team can walk the same time in their own patrol area.

That is to say, twenty-eight patrol teams, twenty-eight patrol areas, each team from one end of the area to the other, and then back, the time spent to ensure that all twenty-eight teams are the same, so that each team can accurately meet the other team at a quarter of the patrol area.

This not only reduces the boredom of patrols, but also ensures that the location of accidents is more confirmed, after all, each patrol team will be seen by another team in any area.

If there is an accident, you can report it to everyone as soon as possible.

Of course, it is not excluded that two teams will be wiped out, and after such a thing happens, the area where the incident occurred can also be narrowed down, and the search scope can be reduced, so as to facilitate the determination of the specific situation of the incident.

The reason is that when the first patrol team sets off, it can see the face of the 28th patrol, and the two sides miss it at the quarter point, and then continue to walk forward, and when they reach the center point of the first area, they can just see the face of the 2nd patrol, and the back of the 28th patrol team just disappears from sight.

In other words, each team can see exactly a quarter of the patrol area in front and rear of the other team, which together is equivalent to half the patrol area.

If the 1st and 2nd teams were killed and disappeared in a place where neither of the 28th and 3rd teams could see, then the area where they might have an accident would be a lot where neither team could see each other, a total of four divisions, which is equivalent to the scope of a patrol area.

However, if other patrol methods are followed, such as the method of segmented patrols and no intersections, the visual range of the same quarter division can ensure that the scope of the accident is definitely within the range of six four divisions, which is directly half the range of overlapping patrol methods.

(This part is drawn for easy understanding)

Therefore, although the overlapping division patrol method seems simple and simple to execute, it is just to divide the partition and control the time, so that it can be implemented perfectly. But the meaning behind it is not so easy to understand.

The alien race does not know the art of war, they can only copy some of the methods of human beings, but they cannot get the essence of it. Therefore, An Xiaoyu is almost certain that although these aliens use overlapping patrol methods, they don't know how to divide or control time.

An Xiaoyu calculated that around this sinkhole, the length of a circle can be more than 3,000 meters, divided into 28 areas, the length of one partition is about one-fourteenth circumference, and the length of four partitions is also one-twenty-eighth, more than 100 meters long.

Even if you count the arc, the arc range of more than 100 meters, in the case of the polar night in the extreme north, it is impossible to guarantee that you can see the other team throughout the whole process. They also have no means of communication and timekeeping, let alone strict military training, and it is a fool's dream to let them complete the cross-overlapping patrol perfectly.

Therefore, after a period of patrolling, the direction and time of their movement must be out of order, and when they see a foreign race appearing, they only need to walk in the same direction as it to avoid being seen for their true faces.

As for how to disguise himself as an alien, it all depends on the copycat gun in his hand.

The green light on the cottage gun can penetrate the night and the wind and snow, making the other party mistakenly think that he is a patrol of aliens nearby, and he only needs to wait until he disappears into the other party's sight, and An Xiaoyu can sneak into the range of the sinkhole.

In fact, it's not that An Xiaoyu is too cautious, although the innate abilities of the alien race are also limited in the Far North, but just like the harassers who created welcome before, it is difficult to say that they can't retain some abilities. And these weird abilities can easily lead to bad things.

An Xiaoyu is not an encyclopedia of alien races, and it is impossible to see what this alien race is and what kind of ability it has at a glance. If you are discovered by an alien race and send a message, I am afraid that you will fall into a chaotic war, and you don't know what the situation is, so it is not appropriate to startle the snake.

After walking for a while, An Xiaoyu found that the alien behind her had turned around, and she was lucky not to meet the person walking on the other side, she secretly calculated the time in her heart, and put the cottage gun into the snow, covering up the green light, ready to pinch the time to come back.

After burying the copycat gun, An Xiaoyu hid her hair in her hat, wore a white hood, and covered herself with a white military uniform, lying on the snow, her hands and feet and moving forward quickly, not even leaving any traces on the snow.

The wind swept up the snow on the ground, forming a fog in the night sky, and An Xiaoyu quietly approached in this fog, passing through a blank area and reaching the edge of the sinkhole. After a little detour around the edge of the sinkhole, An Xiaoyu found the passage for the alien race to enter and exit.

The entire sinkhole goes straight up and down, with a height of more than ten meters, and there is no slope at all. The entry and exit of the alien race depended on a peculiar race, which did not look like an ancient race, but rather like a domesticated beast, with four long claws and a round head, the diameter of the head was about five meters, and it also had a large flat duck beak sticking out directly. 、

The four feet of the beast, two of which are attached to the upper edge of the sinkhole, and the other two fall to the bottom of the first layer of the sinkhole, are very elastic and can be retracted at will. When the aliens want to go up to the sinkhole, they can follow the beast's head to the top of the sinkhole by moving their heads against the cliff of the sinkhole, and they can stand on the wide mouth and rise to the top of the sinkhole with the beast's head.

Isn't this Nima the biological version of the lifting bin? An Xiaoyu looked at the dozen or so monsters on the cliff with a little shock, a row of them was very spectacular, up and down like a scene in a monster movie, with the big scene on the sinkhole, the visual effects were amazing.

An Xiaoyu only glanced at it twice and left here, she definitely couldn't go down from this side, found a remote place, An Xiaoyu fell down and slid down against the cliff. I don't know if the first layer of this sinkhole is full of snow shells, or if it was originally a layer of ice frozen on the outside of the rock.

In short, she doesn't leave her hands on the cliff, and the tricks taught to her by Bei Huang are useless in this kind of place, there is no friction at all, what do you take to keep your body? Therefore, An Xiaoyu can only maintain the minimum energy output, and try to use the geomagnetic field to float up and slide down.

However, this is not a simple matter, the geomagnetic field in this place is chaotic, even more chaotic than the magnetic field outside, and several times An Xiaoyu almost fell directly. This also further affirms An Xiaoyu's speculation about this side, there must be something terrible in this!

Landing at the bottom of the first layer of the sinkhole, An Xiaoyu didn't have time to look around, and directly dodged into a shadow. Fortunately, for these lower races, the alien race is very stingy with their energy and does not light many lights. Grabbing the gap, An Xiaoyu quickly walked through the entire outer layer of the "shantytown" and came to the edge of the second layer.

Lying on the snow, looking down from above, An Xiaoyu saw that the scope of the entire second layer is not large, if the ring width of the first layer can be three hundred meters, the second layer is only about fifty meters wide, only a small area is really a accommodation area, and a few tents are estimated to be reserved for nobles.

The rest of the place was filled with all sorts of tools, as well as several huge beasts and alien races, presumably substitutes for heavy engineering equipment. These beasts and aliens were all covered in a strange layer of slime, and although the slime was liquid, it was not frozen.

Is this an alien antifreeze? Ann Xiaoyu guessed.

Looking at the depth of the second layer, it can be about more than 500 meters deep, no wonder you can't see the second layer from the outside at all, and even the light of the third layer can't be seen clearly. The second layer is already so deep, what is the third layer?

An Xiaoyu became more and more curious.

With a roll of her eyes, An Xiaoyu carefully went around to the other side, stepped on a few not very clear footprints on the snow, the direction of the footprints rushed outward, and she was satisfied to touch her place again, then turned over and jumped off the edge.

As before, An Xiaoyu slipped off the mountain wall, but with more caution. The alien race below is not comparable to those inferior races outside, there must be a lot of masters of the alien race here, one will be discovered if you are not careful, and at a height of five hundred meters, you can't fly, how to run?

Carefully sliding to the bottom of the second layer, An Xiaoyu picked a place full of messy debris as a landing point, carefully avoiding the perception range of several giant beasts. Hiding in the shadows, we came to the edge of the second floor.

The aliens on the second layer are very silent, almost no conversation with each other, and occasionally there are scenes of two people talking, but it is only a short sentence or two, and all of them are in the aliens' own language, so messy that An Xiaoyu can't understand what he is saying at all.

But she figured out which race was in control.

Some other high-level races, An Xiaoyu didn't know, but occasionally saw a figure that went to the third layer, which made An Xiaoyu very sure. The whole body is wrapped in a black robe, and the face inside the robe is clearly transparent.

Hong!

So that's the case, that's why the Hong declared war on the Empire? What exactly are they planning here? What incredible treasure to develop? What kind of big means to make, long-range attack on the empire? Or is it that the team of the Northern Guns has already been trapped here by them?

Thinking of this, An Xiaoyu looked left and right, came to the inner circle of the second layer, and finally saw the thing in the sinkhole with her own eyes.

"Who!"

A thunderous roar came from the bottom of the sinkhole in an instant.

An Xiaoyu's hairs all over her body suddenly exploded, a top master! This is definitely a top master who can compete with the Taishi realm! The whole sound drove all the surrounding ice and snow to tremble, and the Hong clan actually put such a master, just so close to Beiyun?!

She couldn't help but think about it, An Xiaoyu raised her hand and threw out four or five ice needles, turned around in the air, and flew towards the "heavy machinery" around the second layer.

With the screams of the masters of the Hong clan and the screams of the giant beasts, the alien races on the second layer all moved, the power of the law on their bodies surged, and some of them held copycat guns with red lines in their hands, which were estimated to be higher-level goods.

An Xiaoyu didn't have time to care about this, taking advantage of the energy fluctuations in the direction of several giant beasts at the same time, when the alien race went to check and didn't determine his location, An Xiaoyu quickly came to the side of the cliff on the second layer, and jumped more than twenty meters on the ground.

The rock wall was like tofu under An Xiaoyu's fingers, and five holes were cut out in an instant. Such an action, if it was before, An Xiaoyu would not dare to do it. The second floor was so quiet that even a needle could hear it, and the sound of a hole in the rock wall would definitely be discovered.

But now it was different, the footsteps of all the aliens, the roars of the giant beasts, made the entire second layer completely noisy.

An Xiaoyu used the strength of her arm to climb the high mountain wall and climb to the first layer in a few clicks.

Looking back, in the opposite direction of the footprints he had left before, several aliens were pointing and saying something, and several Hong clans in black robes suddenly flew over there. However, the speed of the flight is also pitiful, not as fast as An Xiaoyu's.

"Not good!"

An Xiaoyu suddenly felt a huge force slowly rising from the very center of the sinkhole. That top master of the Hong clan is going to chase him out!

Thinking of this, An Xiaoyu turned around and ran, flew directly out of the third layer of the sinkhole, came to the place where he buried the cottage gun to dig things out, and walked quickly in one direction, and within half a minute, he saw the patrolman on the other side.

Turning around and changing directions, traveling in the same direction as this group, An Xiaoyu sped up, and soon disappeared from their sight, burying the cottage gun in his hand deep again, compacting the snow shell, and turning around to escape from the range of the sinkhole.

With the previous experience, and this time it was almost a tailwind, An Xiaoyu quickly returned the same way, returned to the location of the valley, and saw the valley mouth where Fei Rong and they were stationed.

Seeing An Xiaoyu coming back, Fei Rong asked, "How is it?" What did you find? ”

An Xiaoyu shook her head: "Hurry up, we're leaving!" The other party has a master, and I was discovered. Although I left some tricks behind, I guess they will track it down soon, the valley is no longer safe, and we leave. ”

Fei Rong also became nervous when he heard this, and shouted in the communicator, and the soldiers of Taniguchi quickly packed up and lined up again. After Fei Rong finished packing his things, he took the time to ask, "Where are we going?" There are actually alien masters in this place, why don't you go back to the empire? ”

"No way!" An Xiaoyu shook his head: "This master, even if I was in my heyday, I can't beat it, the speed of the alien race is faster than us, and if you go back, you will only be caught up and then wiped out!" We have only one way to go......"

Fei Rong looked at the depths of the extreme north, he knew that An Xiaoyu was right, if it was to the depths of the extreme north, no one could use the power and energy of the law, and the chances of victory for the human race would definitely be higher. He gritted his teeth fiercely and scolded loudly:

"! Walk! ”