Let me 'splain.
If you have a length of dyed roving, you can split it in half.
Half will be spun in one long piece, making the section of each color very, very long indeed.
The other half can be done in different ways from what I've seen. The way I did it is to split the second half in half and then half of that in half again. I started spinning with the smallest strips and then the wider strip and then the wider strip. So there was a 1/2, a 1/4, a 1/8 and 2 - 1/16 size strips. I started with the 1/16 strips and worked my way up.
My first bobbin was the many strips with longer and longer color repeats. The second bobbin will be the first half strip with its long repeats and then I'll ply the 2 bobbins together.
I have no idea how it will turn out but we'll find out soon.
If you want more information about fractal spinning, see the blog post from Roving Crafters here.