I just finished making the top of an American Flag using the tumbler blocks, and yes, you do have to match up the seams the same as you would any other block. It's straight sewing. Oh, I know what you did. Did you sew them together at the ends of the tumblers or on the sides of the tumblers? They are supposed to be sewn together vertically on the sides, and then the ends will meet easily with the next row. I hope I made myself clear. The rows also need to be sewn together vertically.