The Union Square Quilt Block
The Union Square Quilt Block is a traditional 9-patch that is sometimes called the "Four Crowns." And that's a good name for it since it does appear that four crowns are surrounding the large central Square-in-a-square (SNS) block. Another version of this block has two SNS units nested inside of each other.
It's a fairly easy block to make, but what I find interesting about it is the secondary pattern that is created when you group several of these blocks together.
To see what I mean take a look at the illustration I created below and notice where the sides of the block are connecting to each other: