After flipping through a few more pages, a sheet suddenly slipped out.
Xu Yi took the sheet and unfolded it. It was made of extremely thin hide, yellowed with age. It was several feet long and wide, yet folded up it was no thicker than an ordinary sheet of paper.
He examined it closely. The hide had a formation carved into it, one that seemed strangely familiar.
He immediately took a Ruyi Pearl from his Starry Sky Ring and activated its restrictions. Light and shadows filled the air as one formation diagram after another flashed before his eyes.
This was the Ruyi Pearl Xuan Lengyan had given him. It contained images of every formation diagram in the Golden Core Society's Central Academy library.
Besides this Ruyi Pearl, the other books had naturally been copied as well. Thoughtfully, Xuan Lengyan had sorted them by category and recorded them in Ruyi Pearls.
After searching for nearly half an hour, Xu Yi finally found what he was looking for. Just as he had expected, he had seen the formation on the hide before. It was called the Seven Aversion Palace Locking Formation.
He immediately began studying it in detail.
The record of the Seven Aversion Palace Locking Formation in the Ruyi Pearl was far more detailed than what was carved on the hide.
Xu Yi tucked the hide back into the book and put it away. Then he took out paper and brush and copied down everything the Ruyi Pearl contained about the Seven Aversion Palace Locking Formation. He brewed a pot of tea and settled down to read it carefully.
By now, Xu Yi had become thoroughly versed in several fields of knowledge.
Ultimately, all formations rested on mathematics as their framework. In less than two hours, he had thoroughly grasped the