#lang racket
(require (planet wcy/mpost-wrapper))
(provide main)
(define (A-B-C-D)
  (values (point 0 0)
          (point '1cm 0)
          (point '1cm '1cm)
          (point 0 '1cm)))
(define (main)
  (call-with-values A-B-C-D
    (lambda (A B C D)
      (draw (op-- A B C D 'cycle))
      (draw (op-- A C))
      (draw (op-- B D))
      (for ((p (in-list (list A B C D))))
           (draw p #:withpen (scale '4bp 'pencircle))))))