There were no more good ideas, and it was useless to discuss more, so the group looked up and down, and looked to both sides. The result was really right for Situ Fang: a long gap was really found in the top of his head in front of him, extending almost three-quarters of the entire passage. Zhang Gong roughly calculated the number of steps, and the length was almost 100 meters.

Near the end of the gap, Zhang Gong searched for a long time on the cave wall, and finally found a particularly hidden mechanism contact, and after pressing it hard, the suspension bridge that Situ Fang said quietly and slowly descended, and the whole process took almost a minute.

Professor Chen stood on top of the suspension bridge and exclaimed, "It's really a suspension bridge!" This suspension bridge design was a real eye-opener for me! If you don't pay attention when you put it down, you really won't notice its existence! ”

After saying that, he carefully studied the suspension bridge in front of him, but the more he looked at it, the more strange he felt: no slings were found on either side of the suspension bridge.

Professor Chen asked Zhang Gong puzzled: "I don't deny that this is a suspension bridge, but this is the first time I have seen a suspension bridge without a sling, how did this achieve lifting?" ”

Zhang Gong replied with a smile: "Actually, this is not difficult, there is no way to have a sling without a sling, this end does not mean that there is no end to that end, no outside does not mean that there is no inside, in addition, this should actually be a mechanism that uses gravity balance control, when we walk to this bridge deck, it is naturally put down under the action of gravity, just like a chain flap mechanism." ”

"But this length is quite long, so the force that this center point needs to bear is too great, and how is the center point fixed? How is this possible? ”

"I roughly calculated just now, I walked a total of 163 steps, each step is almost 60 centimeters, then this is about 100 meters, if you want to achieve the balance of this suspension bridge, that means that the entire suspension bridge length needs to be 200 meters, almost half of the entire passage, this is unrealistic, so there will definitely be a sense of sling here, but we can't see it now."

"Even if it's invisible, it should be real, and I'm curious how this can be achieved?"

"What if this suspension bridge isn't monolithic? Rather, it is done in stages? Starting from the front piece to fall, one by one presses the other to cause a chain of falling, forming this suspension bridge, of course, the basic element of the suspension bridge is the hanging, then there must be an article in this cave wall, and the whole organ should be hidden behind this cave wall. ”

"But we didn't find anything out of the ordinary?"

"If the thickness is small, we can easily determine from the sound feedback, but what if the thickness is large? Hitting the mountain to determine whether the back is hollow or not obviously does not give the correct answer, after all, to support such a heavy suspension bridge also needs a strong base, so this thickness will not be too small. ”

"I still don't understand how this suspension bridge works."

Seeing that he could not explain to Professor Chen with theoretical reasoning, Zhang stopped talking and carefully searched for information on the suspension bridge. A few minutes later, he came back with a smile and said to Professor Chen: "I understand the structure of this suspension bridge, this is a veritable suspension bridge, this bridge deck is really segmented, the junction is cleverly hidden by the illusion of the steps hewn out above, and about the problem of slings, they are not absent, but real!" Each section of the bridge deck has a protrusion about 30 centimeters wide extending into the mountain, and the slings should be hidden in the mountains on both sides. ”

"How do you know for sure?"

"If you look closely, you can clearly see the structure, above the protrusions on both sides, there are shelters that can follow the take-off and landing, you see, these stones that seem to exist naturally on the mountain, in fact, can move up and down, they move up and down according to the suspension bridge in the fixed track, thus covering up the raised tracks on both sides of each stone slab, so that you can explain why after entering this passage, the unconventional cave walls on both sides are no longer neat, but irregularly excavated."

"Okay, let's leave that for now, we'll all go up now, and when we get back, we'll try another way."

"But where have the grave robbers gone? Didn't you get in here? ”

When Situ Fang heard this, he felt that his judgment had been denied, and walked up to Zhang Gong a little unhappily and said: "They must have entered this passage, there are obvious messy footprints on the floating soil at the entrance of the cave, and there are no traces on the floating soil over there, which means that they must have entered here!" ”

"Okay, then that means there are other secret passages here, let's be careful!"

After speaking, Zhang Gong walked to the front and led the team back.

But after walking for about ten minutes, they still didn't get out of this passage, and then Zhang Gong noticed the abnormality, stopped and said, "Wait! I feel like we're going down another dark tunnel again! It didn't take much time for us to come in, and now we've been walking for ten minutes, but we're still walking like this. ”

Professor Chen said weakly: "It's a little wrong, we must have entered another space inexplicably, and it feels like we're not walking in a straight line." ”

Situ Fang shone a bright flashlight ahead, and after seeing the pillar of light clearly appearing on the mountain in front of him, he walked up to Professor Chen and said: "I shone it with a flashlight just now, and the front is indeed a curve, about 7 to 8 meters away, and I can't see it if I go there." ”

Without waiting for Professor Chen to speak, Zhang Gong nodded and took over the topic and said: "In other words, the arc of this passage is not too large, so that we are not easy to perceive, the key is when did we slowly enter this road?" You are from a special forces, so you feel better in this regard, you can analyze and analyze it. ”

"I can't talk about the analysis, I think it may have been slowly entered here since we first got on the suspension bridge."

Professor Chen shook his head at the two of them and said, "Don't guess, make a mark here, in case another passage appears when you turn around, do one every 50 steps." ”

According to Professor Chen's request, Situ Fang used a shovel to draw a forward arrow on the cave wall, and the group continued to move forward. After more than half an hour, they noticed the anomaly again: the arrow marks they had made appeared in front of them, which meant that they were going around in circles.

Professor Chen stopped in front of the arrow, looked carefully at the front and side, and said to Zhang Gong: "Old Zhang, we have entered a dead loop!" It should be a closed ring. ”