>    (let recur ((x x))
   >      (if (pair? x)
   >          (cons (car x) (recur (cdr x)))
   >          y))

   But this borders on the absurd, because under this definition,

      (append '(a b c . d) '(e f g)) => (a b c e f g)

   that is, the d is silently dropped.  What kind of sense does that make?

Plenty of sense -- the D isn't doing anything except terminating that
list. Once you get used to thinking of D as an empty list, Lars, you're going
to love it.

OK, I am getting a fairly consistent review here, so stay tuned for
a new compromise.
    -Olin