Free-form Creation myth
The reach appears to be a grand nebula that majestically fills the sky of each other plane, though when a being enters it it turns out to be a small planetoid floating within nothingness.
The planet is fairly small on a cosmic scale, barren and lifeless. In one of the many craters that dot its bleak, ragged surface is a small stone structure.
Stepping through the plain door reveals an infinite number of bookshelves with barely enough room between them for the being to squeeze though regardless of its actual size. The floor plan to this library, as best you can make out from wandering amongst its shelves was envisioned by a crazed genius with each hint of rhyme of reason being replaced in short order by more confusion. The book shelves contain books on every topic one could dream of, each containing all one need ever know on that subject.
From the centre of the ceiling, high above the impossibly high bookshelves hangs a triple pendulum, with a perfect map of existence slowly orbiting it. This feature is visible from all points in the library, somehow being able to be glimpsed over and around the shelves.