I was inspired by the Husqvarna Free monthly project for July to try the circle attachment for my serger, so I cut 10 inch diameter circles from an old mattress pad. Then, I centered a four inch ruler on each circle, and marked around the ruler. I also marked one inch around the ruler. This outer square is the sewing line; I used pins to align the corners before sewing. I connected these circles in a 3 by 4 arrangement. Next, I used the four inch ruler to cut a square for the center of each circle. This fabric was upcycled from an old bed sheet. I placed a square in the center of each circle, then folded the curved edges toward the center of the square, and stitched the curved edges to the squares.
The Husqvarna project is more polished, and would be nice in a living room or bed room; here is the link for their picture and directions - http://new.husqvarnaviking.com/en-US/Be-Inspired/Blog/July-2013/FREE-Monthly-Project-Circle-of-Fun-Cathedral-Pill