My great-great-grandparent is a good person.
When you and another person lay together head to foot with blankets on top of yourselves.
"Hey, you wanna watch Netflix and play Willy Wonka's Grandparents?
Great-great-grandparent's parent.
My great-great-great-grandparent is a good person.
Great-great-grandparent's parent.
great-great-great-grandparent.
The great-grandparent of one's spouse.
My great-grandparent-in-law is a good person.