(deftest bryan-recursion ()
  (labels 
      ((fib (n)
	 (if (<= n 1)
	     1
	     (+ (fib (- n 1))
		(fib (- n 2)))))
       (my-mod (n d)
	 (if (< n d)
	     n
	     (my-mod (- n d) d))))
    (check
      (= 21 (fib 7))
      (= (mod 43 4) (my-mod 43 4)))))