Answer prose round 1: pick key leaves its root rule to pickKey, the worked example lists l's addressed keys, refuseTwiceDrawnIn recurses on an addressed key, the street rule and NANPA's sit where their readers look, and street_delivery cites only what its source states

namefence.go

@@ -66,7 +66,7 @@ func rendersInside(nodes []node, t *template) bool {
 // it, at a spot where the bound spelling could stand. That spelling draws the same without the
 // name: write {/word} for {/word as w}{w}. A bound field can stand in only where the reading
 // template reaches the binder through fields. A single read as a calc operand stands where a calc
-// could not read the spelling, a reference or a path: {/misc.coordinate.lat as lat}{calc(lat * 60)}
+// could not read the spelling, a reference or a path. So {/misc.coordinate.lat as lat}{calc(lat * 60)}
 // stands, since {calc(/misc.coordinate.lat * 60)} does not compile.
 // Where the spelling would be a whole CLI argument or a whole struct tag, that entry point refuses
 // it and names the bare path.
@@ -142,9 +142,9 @@ func refuseTwiceDrawn(addressed map[pickKey]string, read string, n node, key pic
 }
 
 // refuseTwiceDrawnIn is refuseTwiceDrawn over t's own reads of its fields; a reference or a read
-// through a name draws apart from the pick. It steps into each read whose level a read of the
-// name lands on or passes, at that read's key under key: beside {n.w.a}, it refuses {n} where
-// n's format reads {w} and w's reads {a}-{a}, since "w" and "w.a" are addressed.
+// through a name draws apart from the pick. It recurses into each read whose key under key is
+// addressed: beside {n.w.a}, it refuses {n} where n's format reads {w} and w's reads {a}-{a},
+// since "w" and "w.a" are addressed.
 func refuseTwiceDrawnIn(addressed map[pickKey]string, read string, t *template, key pickKey) error {
 	reads := map[string]int{}
 	var into []arm