Sod homes for grazing

I had a friend in Sussex County, New Jersey named Andy, who lived in one of these.  The man he bought it from was a real survivalist and wanted a geothermal home.  He built it literally into a mountain and then laid in water pipes that warmed the floors.  On top of his home, on the sod, he had a goat and a few chickens graze.    The man sold it to Andy because he had come up with some new designs for off the grid living and wanted to try them.