If all eight possible origin choices are considered:

For an alternate, more qualitative explanation of the effects of changing origins go here.

As an example of how this analysis allows the arbitary assignment of a small number of phases, consider what happens if an ooo reflection, an eoo reflection and an ooo reflection are arbitrarily assigned positive phases. The choice of a positive phase for the oee reflection limits the possible origins to #'s 1, 3, 6, and 8; the choice of a positive phase for the eoo reflection further limits the possible origins to #'s 1 and 8; and, the choice of a positive phase for the ooo reflection limits the choice of origin to #1. Thus, these arbitrary phase choices lead to a unique, non-redundant choice of origin: