Outpocketing: Sometimes planar borders bulge and stretch, forming an outpocket, a bulge onto another plane. Outpockets are discrete areas, visible as transparent walls or bubbles on the affected plane. In a way, an outpocket is like a portal, though it's often larger. A traveler inside an outpocket can see features beyond, but they are blurred and indistinct, as if viewed through running water. Some outpockets are stable, and others may slowly shrink or grow over time.
Characters can move through an outpocket wall; the wall's resistance is only as strong as a moderate wind. Once through the wall, the conditions on the new plane apply. Outpockets usually only occur between planes that are coterminous or coexistent, although some outpockets are bulges from parallel versions of the original plane. Such outpockets can reveal possible futures, distant pasts, or barely recognizable presents.
Nested Pockets: Sometimes outpockets form in groups, each pocket nested inside another and connected to a different plane. Thus, they are sometimes called nested planes or nested realities. The walls between nested pockets may look like standard outpockets, or may be invisible. Either way, passing through the boundary is as easy as walking into the wind. In this way, a simple copse of trees could hold nested pockets-whole worlds reachable through deeper and deeper outpockets.
-- Manual of the Planes, p. 220
I have been confused about how the outnested pockets at the end of manual of the planes would function, I need some info how the outpockets can nest;
- Can they be larger on the inside, and is that how they nest?
- And is it possible to use an outpocket to go to an area outside of the outpocket?
I am looking for interpretation, or any other sources referring to this. If you are uncertain about some of the questions, feel free to answer as many as you can.