Flatland. Originally introduced in a novel in 1884, it has become an illustration of dimensional observation as well as a highbrow punchline in the century-and-a-quarter since. It's a 2-dimensional world whose residents cannot comprehend the free movement in three dimensions that we enjoy. The idea is that there's a square that lives on a single plane, unable to exist in multiple segments of the third dimension at one time. It sees the world differently, not understanding our enhanced view.
I've been thinking about Flatland lately. Actually, I've been thinking about the 4th dimensioners that would see us the way we see Flatlanders. We can witness a 4th dimension (time) only in individual slices, but is it possible that there is some being that can exist in multiple points of time the way we can in space? When I look at it this way, time and time-travel for a 3-D being makes so much more sense. It's not that different copies of us exist simultaneously in several parallel time periods. More likely, it is just as it would be with the square moving in the third dimension. When it enters a new plane, it must leave the old one. That's not to say that it has to travel the dimension linearly, maybe it finds a way to drop several units in an instant, but to the other residents of Flatland, it would seem to disappear instantly from one and appear instantly in the other. I think that's how time-travel would have to work for us.
What's more, Flatlanders experience time as well. They are, in fact, experiencing all of the same dimensions as a 4th dimensioner would, but they are only capable of expanse in two of them. Are there other dimensions out there that we are already experiencing one point at a time, but cannot perceive without the continuum? We don't know what we don't know. Dogs don't know that color exists, even though they mingle with those of us who can see it. Do we walk among bees that span centuries? Spiders that span gravitational leaks? Cockroaches must exist in at least six dimensions, right? And if there's truth to any of this, what is the Möbius Strip of higher dimensions? I'd love to take a walk on that!