(load "util.scm")

(display "\nex-2.24\n")

(define x (cons (list 1 2) (list 3 4)))

(define (display-spaces n)
  (cond ((= n 0) ())
        (else (display " ") (display-spaces (- n 1)))))

; Procedure to print a tree (in an ugly way)
(define (display-tree tree level)
  (if (null? tree)
    ()
    (cond
      ((pair? (car tree))
        (display-spaces level) (display tree) (newline)
        (display-spaces (+ level 1)) (display (car tree)) (newline)
        (display-tree (car tree) (+ level 1))
        (display-tree (cdr tree) level))
      (else
        (display-spaces level)
        (display (car tree))
        (newline)
        (display-tree (cdr tree) level)))))

(display-tree x 0)


(display "\nex-2.25\n")

(display "\nex-2.26\n")

(display "\nex-2.27\n")

(display "\nex-2.28\n")

(display "\nex-2.29\n")

(display "\nex-2.30\n")