examples/ex-124.rkt
#lang racket
(require (planet wcy/mpost-wrapper))
(provide main)
(define (main)
  (let* ((u '1cm))
    (draw (op-- (point (op* -2 u) 0)
                (point (op*  2 u) 0)))
    (draw (op-- (point 0 (op* -2 u))
                (point 0 (op*  2 u))))
    (for ((i (in-range -2 3 1)))
         (draw (op-- (point (op* i u) (op/ u  20))
                     (point (op* i u) (op/ u -20))))
         (draw (op-- (point (op/ u  20) (op* i u))
                     (point (op/ u -20) (op* i u)))))))