I have the Strip Tube ruler. I've made several quilts with it. I love it. It's like magic. Let's see if I remember how it works since its been a while.
You sew 2 strips together, then sew another 2 together and place them face to face, nesting them. Sew them together on each side to make a tube. Then use the ruler to cut out triangles and voila! you have a square with the 4 strips in it.
Now that I've typed that I realize that's how I make HST with my Eleanor Burns quilt in a day ruler. So much quicker than other methods.
I got the Strip Tube book with my ruler, but that's because I took a class with it.