parable: a short allegorical story designed to illustrate or teach some truth, religious principle, or moral lesson. From the Late Latin "parabola."
parabola: the set of points in a plane that are equidistant from a fixed line and a fixed point in the same plane or in a parallel plane. See parable.
So what does a mathematical construct and a short story have in common, besides their Latin (and from there, Greek) roots?
No clue. But a teacher in Sunday School today pointed out the similar roots, and I thought it was interesting. He made some sort of point, but my thoughts went a different direction.
I think this is a pseudo-mathematical illustration of a parable. The more we study it (x-axis), the more understanding we gain (y-axis).
However, parables are not meant to be perfect illustrations of a particular doctrine, they're simply rough teaching aids. Therefore, if you start to scrutinize a parable too closely, or interpret it beyond the original intent of the teacher, you start losing understanding, and can even go negative (understanding it incorrectly).
This isn't a particularly deep post, but it was a thought that interested me, so I thought I'd stick it out here...