The word Parallel, by definition, is contradictory and complex. Fundamental to it, is an oddly unquantifiable, spatially related near-simultaneity: two elements existing in related locations, never crossing or intersecting, but also never deviating from their perceived relational existence.
In order to BE parallel, there must first be a perceived relationship or a connection. A parallel relationship often assumes that one parallel object shares characteristics or traits with the other parallel object(s). This parallel condition has the tendency to "rub off" characteristics between the objects.
Being parallel requires at least two; there can never be a parallel of one. However within this relationship of two, there are limits of its two-ness. Because two parallel objects or conditions perceived as "too" separated, too far apart that they no longer are understood as related, are no longer really parallel, even if in fact at some distant scale they are. However, where this boundary lies is undefined and relative to the perceiver. Furthermore, nothing in the parallel definition states that two parallel objects/ideas can't change the relational "distance" between them. Mathematically speaking, two parallel lines that are at one moment 1" apart and the next moment 2" apart, are still parallel. Nor do both of these lines have to be the same in thickness, height, outline or texture or even constant state. Both lines don't even have to be of the same time. Similar lines, say 3 minutes a part, can be parallel.
The parallel condition also requires direction. For example: 2 circles side by side are not parallel. Their form and proximity suggests that they have relationship to each other but, because of their non-directional nature, they are parallel. 4 circles, equa-distance apart, again are not first and foremost parallel. They are a grid, they are a pattern but not necessarily parallel. However 6 circles, in two rows, equa-distance from the circles adjacent to it, are parallel. Technically speaking the previous examples given were all parallel, or at least have parallel qualities, but because of their form (circles), their other more dominant characteristics took precedent, smothering the parallel and making it unrecognizable. Does this mean that the 'parallel' of the first two examples goes away?- no...well maybe.