onacci n i f0 f1)
  (if (= i n)
    f0
    (fibonacci n (+ i 1) f1 (+ f0 f1))))
</pre>

Although there is a named-let analog for the former form, there is none
for the latter.  To wit, suppose one wished to compute the 10th element
of the Fibonacci sequence using a named let:

<p>
<pre>
(let fibonacci ((n 10) (i 0) (f0 0) (f1 1))
  (if (= i n)
    f0
    (fibonacci n (+ i 1) f1 (+ f0 f1))))
Values: 55
</pre>

As it stands, one cannot equivalently write

<p>
<pre>
(let (fibonacci (n 10) (i 0) (f0 0) (f1 1))
