Hi John (& Yong Peng),
> Actually, with all respect, I think perhaps the grammatical
> error is yours. You corrected my "niilassaa" to "niilasse",
> I assume because you think accusative is appropriate here.
> However, I still think nominative case is correct, since the
> blue horses are the subject of the passively constructed
> sentence.
I agree. This is normally the case when a transitive verb
taking a single object is expressed in the passive voice.
With bi-transitive and tri-transitive verbs matters are more
complicated, with the objects' cases in the passive being
determined by the kind of action denoted by the verb.
Best wishes,
Dhammanando