The toString() method, FaderString(), is a bit more complex than its Alternator counterpart. It creates a temporary BodyColor object, and populates it with IntColor objects for each color attribute that is present in both the beginning and ending BodyColor objects. It then increments the current step.
When all steps have been completed, it resets the current step to zero, so the object can be reused. It returns the specified text, along with an embedded BODY tag generated from the temporary BodyColor object.