What about the ancestral Feng Shui in Li Shimin?

Grandfather and grandmother.

granddaughter

Grandchildren and granddaughters

The descendants of ancestors are grandchildren.

Grandpa and grandma are grandmothers and grandfathers.

Grandmother and grandfather are grandmothers and grandfathers.

Grandparents and grandparents are called ancestors.

The descendants of sons and nephews are called grandchildren.

A grandson's son and daughter are called grandchildren.

Grandchildren and granddaughters of grandchildren

The descendants of grandchildren are called grandchildren.