Subsets of a sphere - interpreting a research paper

Suppose that we choose $n$ diameters in a sphere. Each diameter intersects the sphere's surface at  points, defining two hemispheres (one centered at each point.)

Now, a research paper I found (linked here: https://www.mathpages.com/home/kmath327/kmath327.htm) says:
"By choosing $n$ diameters, we partition the surface into a certain number of subsets. Each of these subsets lies entirely inside or entirely outside the hemisphere centered on each of the $n$ points."

I'm assuming that "subsets" refers to regions on the surface of the sphere...

But how does choosing $n$ diameters partition the sphere into subsets? Can someone please describe this process intuitively?

Thank you so much!