They came to the playground and followed Gao Caiqin's instructions to a fence. Lush camphor trees grew inside and outside the fence. They spread their protective umbrella-like canopies, completely blocking all prying eyes.
They looked around the area and found nothing unusual at first glance. The fence is three meters high. If the electronic fence above is added, the height will increase again. If you want to climb out of the wall here, let alone a junior high school student, even those well-trained athletes or parkour experts will have a lot of difficulty.
The gap between each railing is only a dozen centimeters, and it is unlikely that even a child of several years old can pass through it.
Ling Ling pushed each railing one by one. Although the school was built a long time ago and the infrastructure is somewhat aging, these iron generals have been stationed here for decades, guarding this place motionlessly.
If it fails in heaven, it will go to earth. But the ground is also solid and firm, without any flaws.
Ling Ling walked around and around this small area, but still found nothing. Finally, he patted the wall in frustration and asked Gao Caiqin: "Can you identify the people who were sneaking around here that night? Can you recognize their voices? I'll just grab them and show us how to do it, so we don't have to look around like headless chickens."
At this moment, there was a sudden metallic "click" sound.
Looking over again, Wen Qiao already had a removed iron railing in his hand.
"This..." Ling Ling's eyes widened: "How did you do it?"
"Look at the connection points." Wen Qiao pointed her to look at a place with his slender fingers: "There are electric welding points at the joints of other railings, which are fixed on the horizontal railing at the bottom. Only this one does not."
"But I just tried every one and couldn't pull them out." Ling Ling still couldn't believe it.
"In ancient China, there was a construction method called mortise and tenon joints. Did you know?"
Ling Ling nodded: "I've heard of it."
“In the mortise and tenon structure, the protruding part is the tenon and the recessed part is the mortise. The convex part and the recessed part are combined with each other, and the furniture or building can be firmly fixed without using any nails. The exquisitely designed mortise and tenon structure is tightly connected The fit can even reach a level of seamlessness.”
"However, the traditional mortise and tenon structure is used in wooden buildings. Nowadays, many retro wooden furniture also deliberately pursue this antique effect, but this is the first time I have seen it applied to metal structures." Wen Qiao said.
Ling Ling followed his introduction and looked at the joints of the iron railings. Sure enough, there was something unusual.
The railing is a slender column, and the connection and fixation point should also be a circle. However, there is a small square protrusion under this special railing, and the connection and fixation point is a "convex" shape. gap.
"This is a structure called a horse pin in the mortise and tenon joint. When splicing, first put the tenon into the slightly larger gap, and then push it forward to snap into the smaller gap. In this way, the tenon and the mortise fit together Finally, it will not come out no matter whether it is lifted or hung."
Ling Ling exclaimed: "You even understand this!" Then he curiously followed the method he said and did it with his own hands. Sure enough, he could reinstall the railing and it would not move at all no matter how shaken it was. Unless someone knows how to do it, it's impossible for anyone to figure it out.
Gao Caiqin also became interested and took it apart in the opposite direction. At this time, the gap that was originally only a dozen centimeters has expanded to thirty centimeters. I believe anyone who is not too fat can get through this gap.
Ling Ling suddenly thought of something and exclaimed: "That's wrong! Even if Lin Xuerou knew that there was a secret passage here, why did she come here? That day was originally a weekend rest day. If she wanted to sneak into the school, that would be okay, but she If she wants to go out, she can just go through the door openly, and no one will stop her!"
When Wen Qiao heard what she said, his eyes showed a glimmer of approval: "You can teach me."
Ling Ling's heart moved, and her cheeks immediately turned red when she heard his sudden compliment.
Looking out from the gap here, there is still a green forest outside. Camphor is the most common tree used for greening in this city. They are evergreen all year round and always stretch out their soft and dense branches and leaves. They are like a string of wind chimes, rustling when the wind passes by, and like a pair of scissors, they shine in the sunshine. When spreading, cut them into strands. They are an isolated piece of tranquility in the noisy city. Standing in their arms, you can feel cool in the hot summer and sheltered in the cold wind.
After passing through this green forest, there is a river about ten meters long. After crossing the bridge, there is a bustling commercial district.
"So, if Lin Xuerou also knows that there is a secret passage here to enter and exit the school, then she probably came here not to go out that day, but..." Wen Qiao stopped talking at this point.
Outside the fence is dirt ground. Although it hasn't rained recently, the ground is dry and hard, leaving no obvious traces. Wen Qiao still leaned down and observed carefully. After a long time, he pointed to a mark on the ground and said, "Look."
Ling Ling tilted his head and looked for a long time without seeing anything interesting: "What is this?"
"It should be a shoe print of the forefoot. The forefoot part of this footprint focuses on exerting force and is accompanied by a tendency to push back, so it leaves such a shallow mark on the ground that is not easy to leave traces. Arc." Wen Qiao replied.
"If you look at the position of the toe of the shoe and combine it with the traces I just mentioned, you can simulate the direction of this person's footprints."
"You mean... someone came in from here?" Ling Ling was not an idiot. After his prompting, he immediately understood what he meant.
"Not many people should know about this secret passage, otherwise there would be no need to make it so hidden. Therefore, this trace should have been left recently. Perhaps it was left when Lin Xuerou came here that day and opened the door to let people in." Wen Qiao concluded.
Although his reasoning was sound and well-founded, Ling Ling still couldn't accept it because it meant that their investigation direction in the past two days was completely wrong. They spent a lot of energy investigating the surveillance cameras around the school, wanting to know which direction Lin Xuerou went after leaving the school. They also visited the surrounding area, hoping to find witnesses who could provide them with clues. But in the end, Lin Xuerou may have never left school at all.
Ling Ling still wanted to struggle: "Maybe Lin Xuerou went out from here. Maybe little girls like them like to take some unusual paths. What do you think?" She suddenly asked Gao Caiqin, wanting to learn from this little girl The mouth understands the real thoughts of little girls of their age.
But at this time, Wen Qiao looked at her with a strange look.
Ling Ling felt uncomfortable being stared at by him: "Why are you looking at me like this?"
"You two are indeed brother and sister. You both have the same problems."
"What?" Ling Ling didn't understand what he meant, but at least he knew it wasn't a nice thing to say.
Wen Qiao did not answer her, but asked directly: "Has the school conducted an investigation?"
"School? We have asked her teachers and classmates, and also searched places where she might appear, such as dormitories and canteens, but she is nowhere to be seen. If she appears elsewhere, someone should see it and report it to us, right? ..." Ling Ling tried to make amends for herself. They did not conduct a thorough search in the school, but took it for granted that Lin Xuerou ran away from home, or at the worst, was deceived, kidnapped or something worse. In short, it must be She went to an unknown place, but no one thought that she might not have left school at all.
"Then go and investigate quickly." Wen Qiao dropped these words without politeness. “Only action can validate your ideas.”
