This technique is a quick way to fill in the sides of an On Point Quilt by using nine patch blocks. It has no wasted fabric. The corners can also be done simply with very little waste.
The example below is for a 9" finished block using 3" finished squares. To customize this for your block size add 1¼” to the finished size of your squares. For example a 12" finished Nine Patch block uses 4" finished squares or 4½” unfinished squares. So the rectangles would be (4"+1¼”) or 5¼” x 4½” unfinished.