It's Not Rocket Science

My lack of care for the d&d canon has finally come back to bite me now that I'm actually considering the in-universe implications for silly lore decisions, and I'm having a wonderful time.

It turns out that the planes of existence are, for whatever reason, laid out like the spokes of a wheel with the few most physical planes at its centre. There's no overlap between them! Which presents a minor problem for me, someone who now needs to come up with a new structure to explain how the planes where intertwined enough in the first place to become separated. The immediate solution I created was imagining the worlds worst layered cake, each plane stacked atop eachother - an idea which killed itself within seconds of its conception as I wondered "Alright, but then how's there gonna be places like Feywild where the etheral plane bleeds through more?"

My current best explanation is that it works like a density tower, but the mediocre kind you'd make in first year science class, that someone shook too hard. All the liquids are briefly mixed together, before resolving back into their separate densities - or in-universe, only a few moments into in the millenia long process of separating. But because this particular tower sucks, there's imperfections where air bubbles and droplets of other liquids stay stuck outside of the layers they're meant to compose, creating areas in the material plane (and others, but that isn't relevant yet) where other planes are more present. Which I think is a silly solution to a silly problem, and so you can imagine I'm very fond of it :3