I think that the majority of speculation is (IMHO) falsely based on the idea that there "must" be a beginning and an end. It's fair enough to assume that time exists beyond our conception of it, but measurements and markers in time do not. It's hard to imagine, just like absolute nothingness (assuming that there ever has been a point in time at which nothing existed).
So is this like trying to place markers for a "start" and "ending" on the perimeter of a circle? Wherever you put it, it will still be at both the start and end, and the same distance all the way around.
If this is correct, I have a vague personal idea of what a sort of "shape of time" would "look like" visually in 3 dimensions, although obviously that's not really feasible. Bear in mind I have no real knowledge of quantum physics beyond a very basic understanding of some concepts. I base this on a belief that there is no such thing as a "true infinite" number, i.e. one that is literally neverending. This seems logical to me given that the "1" at then end of "1*10^-∞" does not exist; there are an infinite number of 0's before it, therefore we will never actually reach the 1, and therefore "1*10^-∞"="0". Likewise "1*10^∞"="2*10^∞", but in reverse.
In a 2-D representation a circle would seem appropriate given that it has no start nor end. Using "x=1*10^-∞" and "y=1*10^∞"This circle's perimeter would have a gradient of x, and a radius of y. This would mean that since x=0, the line would be completely straight, and of course not a circle anymore; however, since its start must be its end, there is a paradox that means it must be a circle, but is also mathematically a straight line. Also, in order for it to exist in our perceived dimensions, the diameter would need to be 2y. Since 2y is actually the same number as y, its radius is also its diameter, and the only way this is possible while maintaining a mathematically correct shape for a circle would be if both were equal to 0, which would again appear as a straight line that is technically a circle.
This suggests a straight line in appearance but in actuality a curve, and the only way this could be maintained is if the gradient is both a positive number and 0. Which would be x again; theoretically the "1" exists, but it is actually also 0.
Another idea which I have considered is that time, when represented as space like this, is an object in nothingness. While this is hard to picture, so is matter amongst nothing. Since it is nothing beyond the boundaries of time and matter, we can assume that the nothingness is equal to y, and therefore the amount of void that time occupies compared to the total void is equal to x. Since x=0 and y=1, the line has a width of 0, so cannot be seen, but must also exist in theory, hence the width=x.
So visually, all dimensions of the "circle" are 0, yet the circle theoretically exists, (is this something to do with self-perpetuation, "cogito ergo sum" thinking? I don't know). There can be nothing seen no matter how many times it is magnified, because the magnification will always be x no matter how large it is made, but it will still exist... or will it? I confuse myself.
This is just my way of rationalising some concepts which I don't fully understand, and making some big assumptions based on shaky knowledge. What are the flaws of this idea? Could someone explain some of these things further?