Introduction to square houses on the ground: People who settled in Pingchuan still seem to have an unforgettable memory of the caves where their ancestors lived in the Paleolithic Age. Banpo people dig pits to build their houses and erect roofs on the ground to preserve their strong cave-dwelling customs. They also built houses above ground. "Wooden bones covered with mud" is a technique for building walls, and baking on fire is a magic weapon for reinforcement and moisture-proofing. There are 12 large pillars on the foundation of this square house, neatly arranged in three rows. It can be deduced that the form of the roof may be similar to the two-sided sloping roof that is common today. Boards and columns are densely inserted between the large pillars supporting the wall. After being entangled with ropes, the two sides are then coated with grass and soil to form a wall. The foundation treatment of the house is to lay a layer of wooden boards on the ground, apply grass soil on it, and then bake it with fire to form a smooth and hard ground.