The People

[chitspa]

As we all know, for a 2D person to look behind them is to flip over and look up-side down. And when to 2D people meet face-to-face, one person is facing the left and the other is facing the right. This means that when a 2D person is born, they will be facing that one way for the rest of there lives. How can this be related to a 3D person?
Is it possible for a person in a 2D world to be born facing an opposite direction.

[pat]

As we all know, for a 2D person to look behind them is to flip over and look up-side down. And when to 2D people meet face-to-face, one person is facing the left and the other is facing the right. This means that when a 2D person is born, they will be facing that one way for the rest of there lives. How can this be related to a 3D person?

I think the closest analogy for 3-d people is in using the rear-view mirrors while in a vehicle. We're all built with our left eye on our left side and our right eye on our right side (coincidence? I don't think so). Looking in the rear-view mirrors flip-flops left and right on us in much the same way up and down would be flipped for the 2-D person. It doesn't take long to get used to how all of this flipped information integrates with the rest of our world. It does take some time when switching vehicles (especially ones of vastly different size and/or height).

This also brings up another point: a 2-d person could, rather than stand on its head, hold a mirror up in front of itself at such an angle so as to see behind.

[chitspa]

I was noticing that all living things in our 3D world is symmetrical. This probably means that a 2D person is symmetrical with their eyes at the top of their head or one eye on each side of the head. Symmetry should help us understand the body figure of a 4-D being.

[elpenmaster]

not all living things in tetronia are symetrical, but i see you point. if bionians have symetrical features across a line, and trionians have symetrical features across a plane, then tetronians would have them across a realm

[swirl gyro]

I'd like to discus the fingers of a 4D being. Linear things can't knot in 4D (knots must be hybrid line/plane). To hold things with linear fingers in 4D would be like for us in 3D to hold things with a set of floating spheres. Admitedly, I'd like to be in charge of a set of floating spheres... but things can get a little slippery when you're trying to hold something. Perhaps a 4D entity would be well off to have linear fingers and planar fingers? It sounds a little sloppy, but perhaps necessary.

[RQ]

Why would the fingers be linear??????? They would be thin rectangles.

True, yes, symmetry is a key characteristic in living things. Two types: symmetry from all directions (bacteria) and frontal symmetry(people, animals, and such). This is because of natural selection. One side has to be symmetrical to the other even if its "defect" is better, because natural selection would evolve with the "thought" that what it evolved is best, if it survives.

[swirl gyro]

Why would the fingers be linear??????? They would be thin rectangles.

Umm, whatever. By linear, I mean like our fingers. And a good reason for that shape is to reach into tight places. I don't even know what you mean by thin rectangles. They can be linear, or planar, or both, and that's about all. Or volumes, but that would be the whole hand/arm, as fins or wings.

[Keiji]

I think their fingers would be cubindrical or possibly duocylindrical.

[RQ]

The fingers wouldn't be purely linear, because then they wouldn't exist according to the definition of 2 dimensions. Now there could be some wacky universe with no rules, but I'm assuming we're talking about an analogy of this one, so that's why.