Overview
The Stone Sentinel Maze was an array of rocks and boulders thought to be conjured by Zhuge Liang based on the concept of the bagua. The formation was located on Yufu Shore (魚腹浦) by the Yangtze River near present-day Baidicheng, Chongqing, China, where supposed ruins of the array exist. In folklore, when the Yangtze River rises in summer, the formation is submerged, but in autumn, the array resurfaces, with the rocks and boulders still left intact in their original positions.
Lu Xun's encounter
The Stone Sentinel Maze was mentioned in Chapter 84 of the historical novel Romance of the Three Kingdoms by Luo Guanzhong.
Liu Bei was defeated by Lu Xun at the Battle of Xiaoting and fled towards Baidicheng with Lu Xun in hot pursuit. When Lu Xun arrived at Yufu Shore by the Yangtze River near Baidicheng, he felt a strong enemy presence and cautioned his troops of a possible ambush. He sent men to scout ahead, who reported that the area was deserted except for some scattered piles of rocks. Bewildered, Lu Xun asked a local, who told him that qi started emerging from the area after Zhuge Liang arranged the rocks there when he first entered Sichuan.
Lu Xun personally inspected the area and believed that the "maze" was only a petty display of deception, so he led a few men inside. Just as he was about to leave, a strong gust of wind blew. Dust storms overshadowed the sky and the rocks seemed like swords, mountainous piles of dirt emerged while the river waves sounded like an attacking army. Lu Xun exclaimed, "I have fallen into Zhuge Liang's trap!", and attempted to escape from the maze but to no avail.
From Wikipedia (CC BY-SA 4.0).