We're not done! The Earths, vibrating at different frequencies inside the Bleed, are but one small component of the Multiverse. It just happens to be the one we're most interested in. Still, the map shows a lot more. Light side first?
While lines lead from each world in the God Sphere to the Bleed and sometimes beyond even the Monitor Sphere, each sphere is divided from the next by a wall. The Speed Force divides the Bleed from the Gods (so accessible from the Earths; is there a reason it's only marked in the Chaos hemisphere?). The Monitors simply think of it as the Speed of Light. An unnamed green line divides God Sphere and Monitor Sphere, probably permeable (more when we discuss Limbo, below). And the Source Wall stands between the Monitor Sphere and the whiteness around it, marked as both the Source and the Overvoid on the map, and as the "limit of thought" in Morrison's notes. Morrison goes on to say that here lies only Monitor-mind, the Source and the Unknowable. I'm willing to bet we readers are part of that Monitor-mind. We're who monitors even the Monitors.
Beyond it is Limbo, which Morrison used for the first time in Animal Man, where lost and forgotten characters wind up, "where memory and matter break down". Think of it as a repository for people and things shunted out of the observable DC Universe and from which the forces of creation (creative teams) can snatch elements in the next major or minor reordering of the Multiverse. My big question is why there's a Limbo beyond each God plane. It may be a matter of graphic representation. Limbo is actually the wall between God Sphere and Monitor Sphere, going all around the Multiverse, picking up stray forgotten concepts, drawn as pools to show it's a place, not just a frontier.
I'd keep circling the Spheres, but we'd be here all day. How about we pick this up on the dark side tomorrow?