The swirl is based on a c10, without any extra guidelines. Mark your c10 with the thread you will be using to stitch. Then stitch a swirl design in each of the 10 small triangles that make up the pentagons; half of them clock-wise, and half counter clock-wise.
I was afraid of getting confused, so I did all the clock-wise stitching first. When I did that, the only thing to look at is how uneven your stitching is. It was very hard to keep going on it. Now that I am stitching the counter clock-wise triangles the design is starting to appear, and I can tell it is going to work out.
Now I can't wait to see the whole thing! The only thing is, there are 60 of each kind of triangle! Again, I am worrying about running out of thread, but I do have a second spool of a very close color, so I should be fine.