"Maybe it's me... Avrilin raised her hand weakly, "For a while I thought about how good it would be if there were no dead people. ”

"That's right. Basically all the clues are connected. The only question now is what is happening to the world we live in! I clapped my hands and 'licked' my mouth: "In other words, are we really back to the original world?" ”

At one point, the five people beside him were shocked at the same time. Duras was very 'excited': "Where is this not the original world?" Obviously everything is the same! It's exactly the same as my memory. ”

"And how do you explain the current strange phenomenon?" I said slowly, "I just remembered another thing. When the McBius circle space appeared at home, I just watched an American horror movie, which was about the infinite corridor. I went upstairs and my mind was full of the plot from the movie. And then I literally barely got out of my house's stairs......"

At this point, I suddenly stood up as if I had been awakened by something, and my face turned pale.

"What do you think of?" My cousin asked in surprise.

"There seems to be a feeling that I can't put into words. Maybe that's the truth! "My face kept changing, and I waved them not to interrupt my thoughts. After thinking for a long time, he frowned and ordered, "Who has a notepad?" ”

"I have." My cousin 'pulled' out the notepad he was carrying with him and handed it to me.

I let it go casually, ripped off one of the blank pages, and tore out two long strips. Without stopping, he twisted the long note and dipped the ends with the honey on the table. Then the two paper circles were laid flat on the table.

"What is this?" Avril didn't know what I wanted to do.

"It's the Mebius Circle." Kudryash, who had only heard my explanation not long ago, obviously still remembered it vividly, and he immediately answered the doubts and doubts of the 'girl' next to him.

My cousin and Duras looked at me silently.

I smiled bitterly: "Yes, this is the Mebius Circle, it's very easy to make, and I don't want to explain it too much." Mengyue, you dip the two Macbius rings together. ”

When the guardian 'woman' heard this, she immediately smeared both sides of one of the mabius rings with honey, and then picked up the other and pasted it.

The process is very short and mysterious. No one could see how it was glued, but the two Mebius circles were indeed glued together, forming a strangely shaped object.

Although I was mentally prepared, I still couldn't suppress the shocked look. His face was very bad, his body shook a little, and the bitter smile on the corner of his mouth became even stronger: "Sure enough!" ”

"What do you mean!" My cousin was anxious and unbearable: "Don't hang your appetite anymore, just announce the answer, I can't stand it anymore!" ”

"Perhaps." I don't know how to phrase it: "We're really not back to the normal world." This world is not real, in fact, it belongs to the same 'sexual' nature as the other world imagined by my cousin. ”

This time, no one refuted it, just quietly waiting for me to reveal the mystery.

I swallowed again for a while, and then said, "Perhaps, we are in a bottle." ”

"Bottles? What bottle? Kudryash didn't understand at all.

"Klein Bottle!" I slowly spat out these four words.

"Klein bottle?" The three people sitting across from me and my cousin didn't know the term at all, let alone the terrible meaning it represented. They just repeated my words.

Resisting my fear, I explained, "The Klein bottle is not a bottle in the usual sense of the word, but a theory. If you glue two Möbius strips along their only edge, you get a Klein bottle. Similarly, if you cut a Klein bottle properly, you get two Möbius strips.

In the field of Klein bottle mathematics in three-dimensional space, it refers to a plane that has no directional 'sex', such as a two-dimensional plane, and there is no distinction between 'inside' and 'outside'.

The structure of the Klein bottle is very simple, there is a 'hole' in the bottom of a bottle, which now extends the neck of the bottle and twists into the inside of the bottle, and then connects to the 'hole' at the bottom. Unlike the cups we usually use to drink water, this object has no 'edges' and its surface does not end. It also does not resemble a balloon, where a fly can fly directly from the inside of a bottle to the outside without having to cross the surface. ”

When I was stuck in the Mebius space at home, I felt strange, that kind of Mebius circle was so perfect, so perfect that no Mebius circle could compare. The idea itself is a rebuttal. All Mebius circles are of course the same. But if my intuition is not delusional, it means that I am not trapped in a Macbius circle, but in a fuller Klein bottle.

"This is the Klein Bottle." I handed them the thing that the guardian 'girl' had glued to them, it was very mysterious, it was just two long strips glued together, but it seemed very unreal, and people couldn't figure out the principle and way of existence.

My cousin and the others didn't see why.

I sighed, "Actually, it's the first time I've seen this thing. ”

"And you guessed that, too?" Night Peak waited for me to take a look.

I shook my head slowly, "I've only seen a three-dimensional image of the Klein bottle. To be honest, don't mention me, even the most authoritative experts in the world have never seen the actual Klein bottle. ”

Everyone was surprised, and Avrilin stammered, "But didn't you say this is the Klein Bottle?" ”

"Indeed, it is."

Avrilin was very puzzled: "Since it is, and you and Miss Li used a very simple method to make it, why didn't everyone else make a model stupidly?" "Because they can't." I paused: "Specifically, in the normal world, no one can do it. The two Mebius bands must be in the fourth dimension to make it really possible to complete this bonding, otherwise you will have to tear the paper a little. And if it's torn, it's even more impossible to do. For example, if a ball has two sides, the outer and the inner, if an ant crawls on the outer surface of a ball, it will not be able to climb to the inner surface if it does not bite a 'hole' in the surface of an ordinary sphere. The same is true for tire loops, which are divided into inner and outer surfaces. But the Klein bottle is different, on top of it, an ant crawling "outside the bottle" can easily climb through the bottleneck to the "inside the bottle". And we, like the ant, are inside it, damn it, and probably inside. ”