Do a D9P and use these for the corners. The size you have now would work perfect. Just ad 2 solids or blenders in 2 of the colors in this fabric. Here's one someone posted on here. Your fabric would be the one that is the big squares with the dots on them. I love this pattern, it's so simple to do and looks so complicated when it's done. Good Luck..crafty_linda_b
http://www.quiltingboard.com/t-83810-1.htm
Here's a link to a video if you are like me and would rather "see" it done than read directions..
http://www.youtube.com/watch?v=dEjZOXxPazg