1 (defun square-list-solo (items)
2   (if (null items)
3       nil
4       (cons (square (car items))
5 	    (square-list-solo (cdr items)))))
6 (defun square-list-map (items)
7   (mapcar #'square items))
8 
9 (defun square-list-iter (items)
10   (labels (
11 	   (iter (things answer)
12 	     (format t "~A - ~A~%" things answer)
13 	     (if (null things)
14 		 answer
15 		 (iter (cdr things)
16 		       (cons (square (car things))
17 			     answer)))))
18     (iter items nil)))
19 (print (square-list-iter '(1 2 3 4)))