jan Mato's take on pi--
pi is sort of a universal relation (a phrase I borrow from the world of relational databases), so it says that there is something connecting two things and who knows what that relationship is, it could be the same sort of relationship as denoted by "the man *who* makes the bread" The challenge with using toki pona like that is that the basic sentence doesn't allow for the object.
* mi lukin e jan pi pali e pan. (lukin governs the e pan, so this is I see the man of work (with unnecessary pi) and I see bread
But if there isn't an object, you kind of can
mi lukin e waso pi tawa wawa. I see the road runner (I see the bird who runs fast.)
preps taking modifers
mi lon supa lape mi. I'm on my bed. (plain case, no modifier to lon)
mi lon ala supa lape mi. Takes negative modifier
mi lon anpa supa lape mi. I'm under my bed. According the official word list, there are only 6 preps and anpa isn't one of them. So construction like this burst into existence. There are several ways to parse it-- compound preposition, prep with modifier, or the anpa is a place where you are and the rest of the phrase modifies anpa. Without a lot of contrastive structures, I don't think there is a slam dunk way to say what the real answer is. (By constrastive structures, I mean, where linguists come up with lots and lots of legal and illegal examples to figure out what the real rules are)
ni li mani sike tu mi. mi tawa. pali li kalama li wile e mi.