I dithered over the fourth border cornerstone and ended up selecting: Grandmother's Pride (pg 130 of 501 Rotary Cut Quilts). If you've been a reader for a while, you'll have seen lots of grandbaby photos. Since all the squares are tiny (1 7/8"), I had fun going thru the scrap basket of the Civil War prints I'd been saving.
You've probably seen scrappy versions of this block in Blog Land, going by the name Granny Squares. I can see why it's so popular... it's an easy and rewarding block.