What is the function of reverse sand in geomantic omen of Yin House?

If the yin house is really against the water, it is the grave of the rich man and his house. If the grave faces south and the water flows from south to north, then it is against the current, and the sand is actually a mound. If the direction of the mountain also extends to the grave, then this is against the sand. Such geomantic omen, like Ma Benteng in front of a secluded house, is a symbol of great wealth and great wealth. Children and grandchildren are rich or expensive!