It would not be clearer to use 1 instead of car when you were using a pair to represent a tree, rather than a list, and you were traversing the left and right branches using car and cdr.
Yes, I suppose that's something I've never grown quite used to with lisp - that it's lists (as a special form of "leaning" trees) and trees - not arrays and matrices.
I suppose even proper lists are incidental - it's really all about trees (and also parse trees).
