Again, I have to disagree - which I suppose reinforces the whole subjectivity angle. I was positive that Zaphod’s two heads were side-by-side to the extent that it pissed me off a fair bit in the most recent movie adaption (among, let’s face it, plenty of other candidates).

I don’t know if the “layout” of the heads is mentioned or not in the books - I’d have to go back and check - but it’s often quite jarring when a book becomes a movie and doesn’t match my inner vision (and how incredibly unthoughtful of them, to boot).