Actually the middle square is 9 1/2" x 9 1/2" so if you want to make it larger, I would just make the middle square larger say if you want to make it a 12 1/2" x 12 1/2" then the strips wiht out the corner stones should be the same lengh, Then you make the a 12 1/2" x12 1/2" of the two colors you will be using as the strips and then cut a 12 1/2" x 2" strip and sew that on the ends of the color squares you will be using on the outsides of the middle square. Then you cut the number of of strips and you will have the right number of strips with the corner stones and the rest of the 2"x 12 1/2" strips will be with out the corner stones. You might have more strips to sew on but that's ok. you can make it any lengh you want. I hope I was able to explain it so you would understand. I think the 9 1/2" middle square is plenty large enough. You can embroider a design on it before cutting out the square. That's what I would do. I find it easier to center the design. Good luck, Huggies, Fay