When I got home I realized the table runner was going to get really big (23 x 68) and too large or my dining room table. So after reviewing a few other options I decided on one block surrounded by four circular half blocks. The instructions for the center block were included with the Squedge 18 ruler.
Here is my finished Squedge 18 quilt. The whole thing went together in a day and I was able to use fabric from my stash.
Turn off the graph paper cells.
Here is a version I drafted in using the Grays fabric library from Electric Quilt. (This is their free fabric download from March 2013).