Spirals seem to come very naturally to us, even using up left over paint from a sponge often results in spiral like marks.
I have been thinking about where 'inspiration' comes from and I think that you do need to look at works of art and the images that are all around when working to a theme. It’s not copying but rather absorbing and responding to those images, so that they enrich one’s own work and thought processes. One needs to be open to the world around oneself, in my opinion, to be uniquely creative. This is why having a theme is often a good jumping off, or even in, point.
There is a short video about using spirals on fabric over on my blog.