> Both seem better to me, as they have some meaning other than random made up strings (for people who don't use 704).

Calling the lefthand child of a node in a binary tree the "first" and the righthand child the "rest" seems like a markedly worse naming system than random made-up names, to me, because the use of English names seems to be implying meaning that it doesn't really offer.

The idea of a thing with two values, one on the left side and one on the right side is probably a bit more intuitive, but I really doubt it's that much moreso than just saying it has two parts called the car and the cdr. People who've never touched a 704 have been learning about conses as a data structure with two parts, a car and a cdr, for almost 60 years; to most of them, it's just vocabulary you learn now, the same way that numerator and denominator are just arbitrary names to people learning fractions.

I also think it's interesting how much people complain about car and cdr yet it's very rare that people complain about cons, which is just as badly named. It should probably have been called make-pair or something, which I think is a much bigger improvement than car vs lhs. But really, it's 3 words of vocabulary, whose definitions can be completely understood by

    (car (cons x y)) = x
    (cdr (cons x y)) = y

That's not very much to ask someone to wrap their head around, it was meaningful to the original implementors, and for people now there's about 60 years of precedent for using that terminology.