In reading the Bible, or any literature, we are liable to see patterns the author includes. Once such is the chiasm or chiasmus. This is when the first section/word finds an echo in the last. The second echoes with the second last. And so on. It is often represented by A B C C’ B’ A’ (for an example of six elements).
One thing I’ve wondered, and heard from others, is this: would an author really expect readers or listeners to pick up on such a pattern?
After all, it seems we only find the pattern with slow and deliberate reading.
Something I read about Greek months suggests that the ancient world was far more attuned to the idea of a chiasm.
In some [Greek] cities, the middle ten days of the month were counted separately from the first ten, and in most cities the final days were counted backwards
A short history of time, p86.
So, there was widespread counting forwards at the start, then backards at the end. Very odd to may way of dating, of course. But this method – chiastic, though not in literature – was a simple part of daily life.
It seems the ‘oddness’ of chiasmus maybe more to do with my culture, that finding this in the Bible is perfectly reasonable.