Hearing Professor Chen say that there is a road in the road, Zhang Gong asked in surprise: "If we talk about time, the first time we came down must be shorter than the current one, in terms of distance, we will walk at about the same speed now, that is to say, the difference is in the space behind us, where a lot of hidden spaces are indeed detected, if that is the case, there are more choices in front of us." ”

"It's not a question of how much, it's a question of direction; Now we assume that our first route is correct, that is, the space is open, and the feeling of circling downward is obvious, and although what we are walking now is also circling, but it is not the same road, in terms of distance, we must be beyond the first time, since the route is wrong, then let's not continue, first to find the cold source. ”

"You mean to give up where you are and go back to the space you just had?"

"yes, I think there's probably the answer we need."

"Theoretically, what you said is indeed feasible, after all, the distance and time are not right now, only possible in the back, but the key is that you have not thought about it, under normal circumstances, the air conditioner is from the top down, and you can feel the chill when you can stand at the mouth of the passage last night, and now there is no does not mean that the passage is wrong, because if the cold air spreads slowly from the bottom to the top, it will take a long time to over."

"What you said is also true, now we are judging by the distance and time of yesterday's journey, and the time and distance we have spent now must have been exceeded, so we can only go backwards, find the road we took for the first time yesterday, and find the mark I made."

"Okay, then let's ignore the discovery here, and we'll go back after we've made a mark."

Walking back is easy to say, it is nothing more than turning around and walking backwards, but here it is not so easy, and when they actually walk, they find that something new has happened: all the signs they made when they came are gone.

After walking like this for more than 10 minutes, Zhang Gong said: "Lao Chen, the wrong way to go now, we should have been going up, this journey should be over 10 minutes, now you look at the road under our feet, it is beginning to be undulating again, indicating that we have entered a new space." ”

"Yes, we thought we would be able to walk back to the place where the space was switched just now, but now we didn't find it, but entered a new space, which is very strange."

"Don't be surprised, there are indeed too many weird things in here, I'll probe this place again first, see if there are any finds, and now we can only use the information in this to find a way out."

"Well, I'll use the walkie-talkie to communicate with Zhu Gong above, and let him try to open this place again on it."

After a few simple words of communication, Zhu Gong quickly responded to the position he had last night, but after he re-triggered the change of channel, Professor Chen and the others did not appear, he shouted a few times through the mouth of the switch just now, and did not get any response except for the echo. Now it was certain that Professor Chen, and the others had walked into another space.

After Professor Chen learned the result through the walkie-talkie, he stopped Zhang Gong and said, "Lao Zhang, now I think we need to rethink here, although we confirm that the place we are entering now and the place we entered last night are switched through the same mechanism, and the result of the switch is the same, so I think there must be more organs involved here." ”

"I also wonder why there are two spaces in one passage, if it is really one space and one space, then only the designer himself knows the rules of this."

"You think, when we switched the space on it, we entered the place we had yesterday, and now we are walking back from the bottom, this method you repeated yesterday, obviously it was not triggered, and the space was not switched, if it is a switch, it can only be the place where you just said that the hidden space was detected, which is also in the past, after all, you also scanned along the way, and did not find any abnormalities."

"Even if it is triggered there, what does it mean?"

"If it's triggered there, how can the vertical height from the entrance here be more than 20 meters, which means that there is a space connected to one here, and the space we are in now and the space we just entered are also 3 meters high, and these more than 20 meters are enough to do more articles, and you have also detected that there is a lot of space hidden inside, so we must sort out these things first, otherwise we don't know when we will go to another unfamiliar space."

"You're right, but the most critical issue now is that we need to find a way to switch spaces and get out of here, so let's continue to explore."

After speaking, Zhang Gong continued to move forward with a few people.

Professor Chen made a mark on the side and said to Zhu Gong through the walkie-talkie: "Lao Zhu, Lao Wang is still on it now, right?" You ask him to come down and stare at the place where the mechanism is switching, and then you scan it with the field strength meter to see how I can get closest to you, and then we go up there looking for the mechanism. ”

"Okay, I'll do it right away."

While waiting, Zhang Gong retreated, and he said angrily: "Ya, this is not a loop that can be walked, there is no way to the front, but there is a hidden space on the left and right." ”

"Now if there's space on the right side, why didn't you scan it on the passage outside?"

"I'm also strange, it stands to reason that this distance is not a problem for this instrument."

"Are you lazy again? Jumping and jumping scanned? ”

Zhang Gong's face flushed, and he said weakly: "I paid too much attention to my feet, and I didn't pay attention to both sides." ”

"Since it's not circulating, it's easy to say, after a while, Lao Zhu will use the field strength meter to scan the walkie-talkie signal outside, and we'll find a way to get out in the closest place to him."

As he was talking, Zhu Gong shouted through the walkie-talkie: "Lao Chen, Lao Chen, now you take a few steps back and forth, and I'll see which direction has the highest signal strength." ”

Professor Chen pressed the call button on the walkie-talkie and walked forward for more than 20 steps before asking, "How is it?" ”

"No, the signal is attenuated, you go back."

After returning to the place just now, Professor Chen walked more than 20 steps in the opposite direction and asked, "What now?" ”

"It's good, you don't stop, I'll alert you through the walkie-talkie when the signal changes readings."

After Professor Chen walked slowly for more than 40 steps, Zhu Gong shouted at the other end: "You just took two steps and the signal strength has changed, it should be here, I will take a shovel and knock it down on the mountain now, and respond to what you hear." ”

After Zhu Gong quickly knocked three times, Professor Chen's side immediately felt the movement, so he also responded three times, and then said through the walkie-talkie: "Okay, Lao Zhu, you can exit first, let's try it here to see if we find it." ”