(defun fib (n)
  (if (< n 2)
      1
      (+ (fib (- n 1))
	 (fib (- n 2)))))

(defun sum-of (list)
  (labels ((worker (list sum)
	     (if (null list)
		 sum
		 (worker (cdr list)
			 (+ sum 
			    (car list))))))
    (worker list 0)))



(defun odd-of (list)
  (labels ((worker (list sum)
	     (if (null list)
		 sum
		 (worker (cdr list)
			 (+ sum 
			    (if (oddp (car list))
				1
				0))))))
    (worker list 0)))



(defun count-of (thing list)
  (if (null list)
      0
      (+ 
       (if (equal thing (car list))
	   1
	   0)
       (count-of thing (cdr list)))))


(defun test1 ()
  (let ((b 0)) 
    (dolist (one '(2 3 4 5 6) b) 
      (setf b ( + b one))))


(defun sum (l)
  (let ((b 0)) 
    (dolist (one l b)
      (incf b one))))







(defun pair. (x y)
  (cond ((and. (null. x) (null. y)) '())
        ((and. (not. (atom x)) (not. (atom y)))
         (cons (list. (car x) (car y))
               (pair. (cdr x) (cdr y))))))