Chapter 687: Chapter 687: Finding Patterns
The fishing boat backed out of Cave 6.
Asarina seemed alright, but the teacher was in worse condition. Perhaps due to his age, he appeared half-conscious and lethargic.
The boat stopped in front of seven cave entrances.
Pan Xiaoxin looked uncertainly at Bai Youwei. “Sister Weiwei, which cave should we enter this time?”
They had already passed through Cave 4 and Cave 2. Now, Cave 6 was impassable, they had to make a choice again.
Bai Youwei studied the caves and asked Pan Xiaoxin, “Xiaoxin, do you see a pattern between 4 and 2?”
Pan Xiaoxin paused, “They’re both even numbers, and then… there’s only one digit between them?”
Bai Youwei said, “Counting from right to left, there’s a 3 between 4 and 2. If the pattern holds for the next cave, counting forward from 2, which cave should we choose?”
“…7?” Pan Xiaoxin hazarded uncertainly.
Asarina asked, “Are you sure about 7?”
“It’s hard to tell.” Bai Youwei lowered her gaze and spoke softly, “Just now, under the boat, I saw patterns of Ouroboros, seven of them exactly. Near the Ouroboros was a picture of a mermaid, as if… once we leave the safety of the Ouroboros, we’ll be attacked by the mermaids.”
Pan Xiaoxin hadn’t gone under the boat, and thus hadn’t seen those patterns. Hearing Bai Youwei’s words, he realized,
“I see now, the seven Ouroboros correspond to the seven caves, is that right, Sister Weiwei?”
Bai Youwei nodded slightly, murmuring, “At the very start, no matter which cave we chose, we’d not encounter the mermaids since we were at the snake’s head. Every snake’s head could guarantee our safety, but once we move deeper, to the snake’s body, we’d effectively be choosing a closed circular path. We’d have to follow the path corresponding to the specific Ouroboros or we’d lose its protection.”
Unable to contain his curiosity, Along asked, “But how do we know the path corresponding to each snake? Are there any clues in the pattern?”
This was the most difficult part for Bai Youwei.
Because the pattern on the boat depicted a cluster of snakes intertwined, and since the light was dim, it was quite hard to make out the details. Also, due to the mermaids’ repeated attacks, the patterns were severely damaged. Iron plates had fallen off in some places.
“Each Ouroboros corresponds to a certain path that follows its own rules… I can’t find any obvious clues, but their colors alternate between black and red. If the head is black, then the tail is red, the colors are on a perfect cycle.”
Asarina mused, “If the sequence of entering the caves also follows this cyclic rule like the colors, entering Cave 4 first, then move two steps forward to Cave 2, then it’s Cave 7, Cave 5, Cave 3, Cave 1, Cave 6, and back to Cave 4. We’d need to enter the caves eight times to complete a cycle.”
Bai Youwei nodded, “That’s the idea.”
After a pause, Bai Youwei added, “Counting from right to left, there’s one number between 4 and 2, while counting from left to right, there’re four numbers between 4 and 2.”
Upon hearing this, Asarina nodded, “I see. You mean the number of the next cave we choose corresponds to its gap from the cave before. If we started with Cave 1, the next would be Cave 3, then Cave 5, Cave 7, Cave 2, Cave 4, Cave 6, and back to Cave 1. It also makes a cycle through eight steps.”
“That’s just one possible pattern.” Bai Youwei’s voice grew softer, “Should we decide on the caves according to the color hints, or not? Let’s hear your opinions.”
Asarina thought for a moment and looked at Along, “You go down and check, how many color blocks are on those Ouroboros.”