First of all, try not to use "old" stones. Discarded millstones, stone mills and stones belong to the same category, stone bridges and road signs belong to the same category, stone tablets and lettering stones belong to the same category, tombstones and tombstones belong to the same category, doorposts of old houses belong to the same category, flagpoles of military camps and ancestral temples belong to the same category, and old yamen and memorial archways belong to the same category ... Neither category can be used.
The stones demolished in the old house were originally for future use. For example, stone steps can be built to the door, but not under the wall.
In short, it's better to hit a new stone yourself.
I have heard of one thing: a railway worker is building a house at home, and there are no stones on the great plains. If the padding under the column foot is made of brick and cement, it will take two days to harden before the column can be built. In order to catch up with the construction period, this man stole a small piece of railway track from the works section and built it as a stone. Few people always know about it, so it won't spread. As a result, my family got sick and the hospital didn't look good. I found a wise man and told him to dig out the stolen things buried under the pillars at home and return them.