How does one piggyback the rollers for a perm?

I've SEEN it done with coffee stirrers! One layer directly on top of another! Two stirrers per row. The hair is rolled in straight sections with another section directly on top of it. there are 2 stirrers (one left, one right) on the section of the rod where it starts to dip in. The next layer of rollers is done directly on the top of it. the stirrers separate & support the top layer from the bottom