functions with uninterned names in CLISP

(defmacro define-some-things ()
  (let ((f1 (gensym "fun1"))
        (f2 (gensym "fun2")))
    `(progn
       (defun start (n)
         (,f1 n))
       (defun ,f1 (n)
         (if (zerop n)
             (list ',f1 n)
             (cons ',f1 (,f2 (1- n)))))
       (defun ,f2 (n)
         (if (zerop n)
             (list ',f2 n)
             (cons ',f2 (,f1 (1- n))))))))

(define-some-things)

; CL-USER> (start 4)
; (#:|fun137185| #:|fun237186| #:|fun137185| #:|fun237186| #:|fun137185| 0)