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After hearing the old Daoist say that, Bai Qi's face was filled with doubt. He said in surprise, "What?" Yin Yang Wall, what is that, why have I never heard of it! "

The old Daoist smiled and replied, "You have never heard of this kind of wall. It's very normal. If it wasn't for you suddenly recalling it just now, I'm afraid that even I would have already forgotten its origin