Qinglong writes according to this style for the east.
The land outside this brick should be in the east of a building.
There should also be a white tiger, a good suzaku and a good Xuanwu in other three parties.
The blue brick was determined by the firing level technology at that time, and has been selected as the brick for geomantic layout ever since.
This thing you found is part of the city residential feng shui array.
Cinnabar can exorcise evil spirits. Qinglong White Tiger Suzaku Xuanwu is a four-sided beast, which can keep the house safe.