One thing that l believe you did in your sample, it looks like you sewed into your seam allowance. This block appears to have set in seams. You have to stop 1/4" from each corner so you can set in the abutting seam. It looks like you may have sewn all the way to the edge of your fabric. Each unit, where it meets has a set in seam by the looks of things.
Try to find instructions on doing a traditional Tumbling blocks with a set in seam as the pattern appears to have a similar construction. The book Quilts! Quilts!! Quilts!!! has good pictures and diagrams to show how you do it. Good luck!