SICP 問題 2.48
(define (make-segment v1 v2) (make-vect v1 v2)) (define (start-segment seg) (car seg)) (define (end-segment seg) (cdr seg))
(define (make-segment v1 v2) (make-vect v1 v2)) (define (start-segment seg) (car seg)) (define (end-segment seg) (cdr seg))