For simplicity, we consider only the following part of the norm example:
or/2 occurs two times in the first argument column; viewing the selected clauses as a new procedure:
Note that the or/2 case of the struct 1 node points (`down') to the type 2 node (`depth') under the assumption that the second query argument may further index the or/2-sub-procedure.
That this assumption is false (clauses 2 and 4 cannot be discriminated) is again due to the structurally identical first and second arguments of the example.