One of the consistent decorative elements at the Dana House by Frank Lloyd Wright in Springfield, Illinois was the large stone urns. They capped many of the walls and accented the house with their rounded shapes. They were a massive 4 feet in diameter and used for different functions, mostly flowers.
They sat on top of the cream colored brick walls at various locations.
They were again used just a few years later on the Darwin Martin House in Buffalo but they had evolved into a different theme of Round and Square:
Notice the similar capped horizontal bricked walls at the Darwin Martin House in the last two images.