values takes any number of arguments, and passes (returns) them
to its continuation.
thunk must be a procedure of no arguments, and proc must be
call-with-values calls thunk with a
continuation that, when passed some values, calls proc with those
values as arguments.
Except for continuations created by the
procedure, all continuations take exactly one value, as now; the effect
of passing no value or more than one value to continuations that were
not created by the
call-with-values procedure is