@@ -76,7 +76,13 @@ Regular: **2-fixed**
7676##### Discussion
7777
7878`$|` takes two arguments, a mold and a gate that produces a `flag` or loobean that is used to validate the structure produced by the mold to ensure that the noun
79−has a certain shape. It crashes if the input fails the validation test.
79+has a certain shape. It crashes if the input fails the validation test. Else it
80+produces a mold-gate that does the following.
81+
82+`$|(a b)` is a gate that takes in a noun `x` and first pins the product of
83+clamming `a` with `x`, call this `foo`. Then it calls `b` on `foo`. It asserts
84+that the product of `(b foo)` is `&`, and then produces `foo`. This sequence of
85+events can be seen from the Expands To section above.
8086
8187For example, the elements of a `set` are treated as being
8288unordered, but the values will necessarily possess an order by where they are in