I don't know what the "three laws of writing" are, per se. There's no mention of that phrase in the novel Wuthering Heights.
Do you mean any of these?
· 3 types of literature: fiction, poetry, drama
· 3 act structure: beginning (problems), middle (climax), end (resolution)
· 3 way relationship: WRITER, READER, TEXT
· 3 appeals in rhetoric: LOGOS, ETHOS, PATHOS
· 3 points-of-view: 1st Person (I); 2nd Person (You); 3rd Person (S/He)
· 3 verb tenses: PAST, PRESENT, FUTURE
· 3 prose styles: PLAIN, SWEET, and STUFFY
This last one, in particular, is a measure of a speaker's style and, therefore, most relevant to Wuthering Heights.
- Lockwood is a kind of stuffy (logos) narrator: his narration is very logical and full of formal language, since he's an outsider:
Joseph mumbled indistinctly in the depths of the cellar, but gave no intimation of ascending; so his master dived down to him, leaving me vis-a-vis the ruffianly bitch and a pair of grim shaggy sheep-dogs, who shared with her a jealous guardianship over all my movements. Not anxious to come in contact with their fangs, I sat still; but, imagining they would scarcely understand tacit insults, I unfortunately indulged in winking and making faces at the trio, and some turn of my physiognomy so irritated madam that she suddenly broke into a fury and leapt on my knees.
- Nelly is a kind of plain (ethos) narrator. She is a servant and uses simple, intimate language to describe Heathcliff:
I was all flour making the Christmas cake, and it would not have done to give me a hug; and then she looked round for Heathcliff. Mr. and Mrs. Earnshaw watched anxiously their meeting, thinking it would enable them to judge, in some measure, what grounds they had for hoping to succeed in separating the two friends.
Joesph is a sweet (pathos) narrator. He uses highly informal language and slang since he is both a servant and uneducated:
That's father! We've allas summut o' either side in us. Niver heed, Hareton, lad -- dunnut be 'feared -- he cannot get at thee!'