The center block and corner posts are created with two different sizes of blocks using the Creative Grids Square on Square Trim Tool for 3 and 6-inch blocks. The six-inch blocks make the center and the three-inch blocks make the corner posts. The diamonds are simply paper-pieced. And, since everything is trimmed to size after cutting sewing and pressing, all of those units go together like a dream! 21-1/2in x 48-1/2in. Creative Grids CGRJAW7 is required.