The bricks on the ground are all square... curved square bricks, and the walls are made of the same bricks. The only exception is the entrance of the room, where there is a complete strip-shaped stone block.
Presumably, that block is where the gate is placed.
In fact, hints are everywhere; one just needs to closely observe and think to understand the meaning behind them.
After securing the deadly rolling ball, the three walked outside, and Luo Heng smiled and said, "Next, as long as we do the same thing as this time—secure the deadly rolling ball at each intersection—passing through will be easy."
Upon hearing this, the atmosphere suddenly became heavy, and Chen Qingyun and Lu Yu instinctively became alert to their surroundings.
Luo Heng also sensed the stagnant air, looking at the two with some confusion, not immediately comprehending.
A moment later, Chen Qingyun and Lu Yu breathed a sigh of relief, and Chen Qingyun remarked, "Looks like there's no surprise this time."
