What's the use of Eight White Stones in Feng Shui?

(1) two arrays of eight white stones, which are respectively placed in the northeast and southwest of the house or room;

(2) an array of eight white stones placed behind tables and chairs or in the middle of the bottom of the house as a popular backer;

(3) A row of eight white stones, placed on the northeast window sill, will flourish and dissolve the poor water in Northeast China.