It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is zero, and that any people you may meet from time to time are merely the products of a deranged imagination.
We know only what our senses tell us, true, and facts may differ from what our senses tell us (Thank you Obi-Wan Kenobi), but for there to be such a massive deceit by our senses so as to render everyone and everything we know to be a mere byproduct of our psyche is like saying we're merely pixels on a computer screen to be changed and recycled endlessly with no knowledge of what exactly we are, nor any way to find out.
I much prefer my own interpretation of inter dimensional travel. While our world holds one set of laws of perception, biological composition, genetic composition, and other such things, another dimension is altogether far removed from ours. While our humanity is limited in perception and biological and genetic makeup, another dimension could hold enlightened non-human sentient life whom are more advanced than we are in the same amount of time.
I think many cultures and religions have elements of the truth in them, but like anything as varied as the human race superficially, they're united at a single set of common ancestors whom likely had the most of the truth within them.
But I digress.
For now, suffice it to say that shrimp skewers and potato wedges with seafood pasta, shrimp scampi, and cheddar biscuits is the most delicious meal I've ever had, and screw anyone who would shoot a roof off of a hot tin cat without first calling dibs on the pancake batter!
The world cannot be a 2-Dimensional shape such as a triangle or a square.
The terms you're likely looking for are Pyramid and Cube, as if the world was 2-Dimensionally shaped, it would be flat, and people would have fallen off of the edge.
Now you know, and knowing is half the battle!