Another valid perspective on all the universes in this chain is that they can be seen as concentric circles (see Filbert’s “Excalibur Revisited”), with the 1st-U (More/Less) being the largest circle and the Bottom-U being the smallest.
This perspective illustrates the fact that each universe is formed by adding limitations (additional Game-Rules) to the state of the one above, thus each universe has less scope (in terms of the range of possibilities allowed inside it) than the one above.
When beginning to look at universes, it can be easy to get confused between them, because there are similarities which occur in many different universes and planes. For example, there is one plane of the Physical-universe which behaves like the Magick-universe which is where most of the energy-bodies exist (see energy-bodies.org for more info).
Each universe has a game, with Playing-field and support structures (including Rules of the Game, and Rules of how the Playing-field works and what it is made of, such as a Matrix of items in this Physical-u and a few other universes near this one).