1. A Single Plane
Everything is composed of planes, or spheres, but the spheres are so immense that even to our primitive instruments they seem to be infinite and flat. This is a singularity, existence in one dimension. This is an incredibly weird environment, and theoretically only exists in black and white holes, and the remnants of superstrings. It all binds together, black holes create artificial singularities, crushing everything down until it can only exist in that monodimension, infinite mass at infinite velocity. The white hole is the postulated other side, where singularity can no longer be sustained and that material must unpack itself, and it unfolds. It unfolds spectacularly, in tremendous displays of light, matter, noise, and more. Everything that is can exist within a singularity until it either loses infinite mass or infinite speed.
2. The Flat Universe
TIME X SPACE
The Flat universe exists in two dimensions, and shapes and ideas can exist within it. Like the pages of a book, or a drawing, or single celled organisms living within a film, the universe is knowable, and to use, easily observable. If the monodimension is infinite infinity, the Flat Universe has opened up to give time and space. Things can move within it, but their ability to interact is limited, and the existence of life within such a dimension would be akin to studying characters within a book. To those figments on those pages, we readers are godlike hyperdimensional beings. We can lift their entire universe in a hand, and move through their time and space with ease. To us, they are fixed, trapped, incredibly finite, and lacking in depth and dimension.
3. The Third Dimension
TIME X SPACE X MATTER
Hello, welcome to your home, the 3rd Dimension.
TIME X SPACE X MATTER X SIXFOLD
It is a fancy name, conjures up all sorts of things, starships shooting through fields of stars, wormholes, anomalies, a sky full of Doppler altered light. Not that exciting, and that is purely imagination. The Fourth Dimension is the Sixfold potential. Within the 4td dimension everything has two potentials, matter has six dimensions, fixing a coordinate in space takes not 6 points but 12. Time is not linear, it is a grid of timelines.
I think that if there are sentient hyperdimensional lifeforms, we would be as frozen and static to them, as the characters in a book are to us, or they experience our dimension the way that we watch television, we can can do much with and around it, but our ability to interact with it is minimal. Almost makes religion look like a call in reality entertainment show for these extradimensional beings.