In a sheet of paper(2D), if a sphere enters it/passes through it, from 2D world's view, circle will get bigger and bigger and then after some time, size will become smaller and smaller and eventually disappear...
Similarly, for a 3D world, 4D object will appear as a regular 3D object but if it moves away in time or some other dimension whatever it is, it will eventually get smaller and smaller and eventually disappear....
So a 4th dimensional creature will appear as a 3D creature but it can traverse and become smaller or larger,so a 4d creature will have some original size and it will become smaller when going out of the 3d world and larger when moving in.....
The 4D creature can see all aspects of a 3D world just like we can see a 2D world made up of atoms, let's suppose we have a long sheet of paper, we can see it and interact with that layer of reality that constitutes it and pull or push it(sheet), so same for 4d creatures, they can see everything of space if space is 4th D, if we consider time as the 4th dimension, then it can see how the 3d world changes with time, but we humans can see that at an instant only, so what exactly will the 4d creature see? Complete past and future of the 3d object?we are 3.5d creatures?
For a 2d creature, it won't know that it exists in a 3d world, but it actually exists within one, without it knowing and it will be very difficult for it to become a 3d creature. Consider a stick figure having brain,how is it supposed to transform itself into a 3d creature?the answer may provide insight on how to become a 4d creature...i think if there are other universes, this might be true as the fabric of reality that constitutes our universe can be considered a 3D space and there might be many more universes out there, so a 4d guy can just choose to pass through our universe, he will appear into existence from a very small size and eventually appear in a certain form
Similarly, a question that, what are forces of nature made up of?Other dimensional creatures will nees to use them in order to come to existence or maybe not as they should have an automated mechanism,only a 3.5 creature will nees to do that via some external means and not created by the universal forces automatically we are made of particles of the 4th dimension?
Just like 3d is made of 3, 1ds so 4th dimension is also made of 4, 1ds : 3d+(time/forces controller?)?force controlling ability should be there as without it,they wont be able to create their existence as a shadow of reality from the 4th dimension.....
But this might be different as well, let's consider a computer.
On computer, at first we could play only 2D games,now we can play 3D games.
In future, we could even invent Virtual Reality to connect our brain to enter a fictional world maybe even removing the memories of brain temporarily.
In this way, we can phase in and out of existence to that world.
All the energy needed for survival of the fictional universe is provided by the energy of some other universe and is just a simulation stored within the registers and circuits of a computer.
What about black holes? Black holes are said to even take away the information of our universe. Is it acting like an observation point? or some kind of node or energy center within the register or CPU of a computer.
What role do black hole play if our universe was just a simulation? A sink that acts as an observation point or just an energy center.
How can we get out of the game world if we are trapped inside of one?
When will the 4D creatures for us (I think 4D creatures are relative to different universes) Their universe might have different sets of physical or universal laws and maybe it is not a computer world but a world like a cultivation world where people can bend the rules of that 4D universe and create 3D universes.
We humans are a machine learning program, we extract and sum up our results of life into our sub-conscious etc etc
Should we also simulate a universe based on some rules and spread some AI creatures on it in order to decipher and learn from what useful technologies the simulated world could bring us.
We could just increase the processing power to a very high level in order to speed up the time and slowly get the technologies created by the game world.
Even though there is a risk for the game world's AI to come out to the real world, but if the time flow is kept just a little ahead, we will be able to get more benefits to the technological level.