Or perhaps "lo spesi'u ku poi crino". It has always been said that "lo broda poi brode [ku]" is different from "lo broda ku poi brode"."ko'a poi brode" has to be the latter, since the restriction applies to an already complete sumti.
But, using the convention from the text, we would read it another way. {lo spesi'u} would still, of course, refer to a couple, but then the relative clause would act on the reference of {lo spesi'u} to extract a part of it that is green, even if it does not form a couple any more. The relative clause can, then, create new possibilities of reference. It is still restrictive in the sense that it takes a reference and then restricts it to a part of it.
That's how "poi" works with quantifiers after all. "ci ko'a poi broda" quantifies over the referents of ko'a restricted to those that satisfy broda.
Only now could I come up with this last interpretation. It surely wasn't intuitive to me. I will reflect on its consequences. But for now, what do you think?
But is there any other interpretation even available for "ko'a poi broda"?