The sentence that uses a subjective pronoun correctly is the first one - Laura and I have written an original play for this year's festival.
The second sentence is incorrect because the word him is not subjective, and neither is her in the third sentence, or them in the last one.
The horse is the direct object
The main idea is that love is different in some societies
This is due to the given perspectives that the story is read from. Also, another person may personally relate to the events in the story in different ways than others, and therefore interpret it differently.
