When Yu Yan went out, Zhao Jinghe watched her go far, which covered the door. Instead of talking with Lin Xie immediately, he started pacing in front of the hospital bed with his back. Lin Xie's face was calm. He guessed what YuYan's grandfather was going to do. He didn't speak first, so they were silent.

Zhao Jinghe walked back and forth for 12 times. Lin Xie counted clearly with his ears. Each circle was eight steps, and the frequency of each step was the same without any deviation. He conjectures: if it is sprinkled with lime, it is estimated that the sixteen footprints can be clearly seen. Is this...