1 665c255d 2023-08-04 jrmu (define (append! x y)
 2 665c255d 2023-08-04 jrmu   (set-cdr! (last-pair x) y)
 3 665c255d 2023-08-04 jrmu   x)
 4 665c255d 2023-08-04 jrmu 
 5 665c255d 2023-08-04 jrmu (define (last-pair x)
 6 665c255d 2023-08-04 jrmu   (if (null? (cdr x))
 7 665c255d 2023-08-04 jrmu       x
 8 665c255d 2023-08-04 jrmu       (last-pair (cdr x))))
 9 665c255d 2023-08-04 jrmu 
10 665c255d 2023-08-04 jrmu (define x (list 'a 'b))
11 665c255d 2023-08-04 jrmu (define y (list 'c 'd))
12 665c255d 2023-08-04 jrmu (define z (append x y))
13 665c255d 2023-08-04 jrmu z
14 665c255d 2023-08-04 jrmu (a b c d)
15 665c255d 2023-08-04 jrmu (cdr x)
16 665c255d 2023-08-04 jrmu <response>
17 665c255d 2023-08-04 jrmu (define w (append! x y))
18 665c255d 2023-08-04 jrmu w
19 665c255d 2023-08-04 jrmu (a b c d)
20 665c255d 2023-08-04 jrmu (cdr x)
21 665c255d 2023-08-04 jrmu <response>
22 665c255d 2023-08-04 jrmu p
23 665c255d 2023-08-04 jrmu What are the missing <response>s? Draw box-and-pointer diagrams to explain your answer.