I'm new to the board and despite the fact your post is over a year old, I'm replying. I've made 2 circular table toppers using a 12 pointed star pattern I made up. Using the 30 degree angles on your 6 x 24 ruler, cut out sizes just as if you were cutting out 60 or 45 degree angles (6 or 8 pointed stars). The width of the strips would be the same as the width of your angle cuts. Lay out the diamonds on your design wall. Measure the distance between your outter points, about 2 to 3 inches above the points. Then measure straight down to the valley, where the diamonds meet. Round up your measurements to be equal and make a square. (If the distance between your points equal 10 3/4" and the measurement down reads 11 1/2" round up both to 12" square.) Finger press the center of one edge of the square and make a small mark. From this center point cut outwards 30 degrees, flip ruler to other side and cut outwards again. This will give you an arrow shape. That shape fits into the "V" area of your diamonds. Mark your 1/4" lines and sew as you would a 6 or 8 pointed star. As you attach units you will need to trim off the excess fabric that is towards the outter points. If you don't have excess then you haven't cut your squares wide enough. I condense 12 seams down to 6 at the center point by sewing squares onto two attached points, flip and trim to equal the angle and then cut off the original points. This give a wonderful center hexagon to the top. I've taught this as a class and is very popular in our shop. Cindy in Washington