Clay was not only used for making the walls, otherwise Bi Fang would not have gone to such lengths.
He also used clay to build a blast furnace, for iron smelting, which all required clay material.
Bi Fang inserted a stick and started to stir the clay and water, just like mixing cement, and soon a layer of gray water surfaced on top of the clay pit, accompanied by sand and silt.
"Has anyone washed gluten before? It's when you wash the starch off the kneaded dough in water until you're left with a sticky ball of gluten—our process is similar to washing gluten."
After a while, Bi Fang scooped out the washed clay, drained the moisture, and successfully obtained a usable lump of clay.
Having removed all the clay, Bi Fang quickly ran into the woods and soon dragged out several thick vines, as thick as wrists, then he dragged the vines in circles around the shelter.
He did not connect the ends together, leaving a one-meter gap as an exit.