Polishing can create a relatively flat surface on the wood.
Additionally, he can process flint to produce serrated edges, with its edges being uneven. If Ma Lin made a hole in the wood and wanted to correct the shape of the hole, he might try polishing it with sharp stones. Furthermore, ropes can also be polished, starting with coarse cords, then using fine ropes.
He has a piece of paulownia wood in his hand, and he is trying to make it into a plank.
The shape of the paulownia wood is very irregular.
This particular paulownia tree itself was broken, and he smashed it down with stones into such a large piece.
He needs to make its shape more regular.
To make a bench seat, a rectangular cuboid, with flat surfaces on all sides.
He has the clumsiest method, which is to keep grinding it on stone.
As the saying goes, constant effort yields results, grinding an iron rod into a needle.
The paulownia wood itself isn't very sturdy, and grinding it on stone makes it smoother.
