Help with personal thoughts and observations in attempt to understand the fourth dimension better

Based on info found in this forum, I have compiled info along with personal thoughts and observations in attempt to understand the fourth dimension better

any input or corrections would be helpful, along with links to sites you have found helpful in your experience.
Thanks! My notes below:Observations:

Move up/down

Move left/right

Move forward/backward

(Age [one direction])
2d circle in 1 dimension is a line getting larger and smaller

3D circle in 2 dimensions is a circle getting larger and smaller

4d sphere in 3 dimensions is a sphere growing and shrinking

What does 4d shape look like? Tesseract? Hypercube?

How does it work?
Possible dimension- Time

Visualized in 2d as a straight line

Visualized in 3D as a straight line

Conclusion: time is a straight line which any point can be accessed through any point all the time.
Time never started and never stops (different from eternity) TIME OPERATES IN A LOOP (time never started and never stops but with infinite time matter will reassemble itself into every single possible combination) given that time is relative and infinite. Light and time are distorted in a black hole (general relativity)
2d timeline is 2d, only exists in 2+ dimensions (too simple) 3D timeline only exists in 3+ dimensions (2d cannot hold due to lack of dimensions.) proposed 4d timeline only exists in 4+ dimensions (3D cannot hold due to lack of dimensions)

Does not exist in any dimension above current dimensionUndefined

Cannot be defined

Time is not infinite (nor finite)
There is Never nothing. Point=0 dimensions

eggy said:

2d circle in 1 dimension is a line getting larger and smaller

The way you would say this technically is that the foliation of a 2D disk into an ordered series of 1D submanifolds is a line segment that gets larger and smaller as you progress along the series.

eggy said:

3D circle in 2 dimensions is a circle getting larger and smaller

4d sphere in 3 dimensions is a sphere growing and shrinking

Similarly with these.

eggy said:

What does 4d shape look like? Tesseract? Hypercube?

What does a 3D shape look like? I don't think this is a well formed question.

eggy said:

How does it work?

How do 3D shapes work? I don't think this is a well formed question either.

eggy said:

Time never started and never stops (different from eternity) TIME OPERATES IN A LOOP

It is certainly possible to produce solutions to the Einstein field equations with closed timelike curves. But there is no experimental indications that support the idea that such spacetimes represent reality in any way.

eggy said:

Undefined

Cannot be defined

Time is not infinite (nor finite)
There is Never nothing. Point=0 dimensions

None of this communicates anything that I can tell.

these were mostly just brain dumps i did in geometry class. I am a freshman in high school and was just asking for input (which you provided). I have virtually no knowledge of any theoretical physics, yet have a huge interest in it. Thank you for the input, is there any way you could include some links to things that i could use to grasp this idea?

Here is one that I found recently.

https://cs.westminstercollege.edu/~ccline/courses/phys301/spacetime_diagrams.pdf

The 4D geometry you are interested in is very useful for understanding relativity. Spacetime diagrams can help you understand a lot of the geometric content of relativity. Although you do have to be careful since there are some important differences from Euclidean geometry.