10Aug/090
Exercise 2.25 of SICP
Exercise 2.25: Give combinations of cars and cdrs that will pick 7 from each of the following lists:
(1 3 (5 7) 9) ((7)) (1 (2 (3 (4 (5 (6 7))))))
> (define a (list 1 3 (list 5 7) 9))
> (car (cdr (car (cdr (cdr a)))))
7
> (define a (list (list 7)))
> (car (car a))
7
> (define a (list 1 (list 2 (list 3 (list 4 (list 5 (list 6 7)))))))
> (car (cdr (car (cdr (car (cdr (car (cdr (car (cdr (car (cdr a))))))))))))
7