My comments on an article on Genesis and Poetry:
The narrative structure of Gen 1, while it contains a sort of rough parallelism, is more like a deliminted list, as we'd call it today. It has a list structure similar to the ordered lists used in computer databases, with regular structure of incremented counts, start and end markers and a content section.
Blocher calls it a list, and it is in general structural conformity with the many other narrative lists scattered throught the pentateuch and historical books of the OT (this would be worth a solid academic study by a Hebrew scholar). The point of a narrative list is that it makes communication both memorable and unambiguously efficient; its over-arching dual structures of the two groups of three days, and the rough chiasmatic structure also go toward improving its memorability.
Prior to the use of punctuation and typograpical hints to the interpretation of texts, I hazard the guess that the sophisticated structures of grouping and patterning of texts, such as chiasmis performed the role of demarking text units to draw understanding of what was being communicated.
