anchor.diff:                        unit 
                         (+ degree scale))))
   
  +;; (make-measurement-1 1 :m 5)
  +;; => #<METER 100 km {1003FF93A3}>
  +;; (measurement-magnitude (make-measurement-1 1 :m 5))
  +;; => 1
  +
   ;; (make-measurement-1 1 :m 3)
  -;; => #<METER 1E+3 km {1003FF93A3}>
  +;; => #<METER 1 km {1003FF93A3}>
   ;
   ;; (measurement-magnitude (make-measurement 1 :m 3))
   ;; => 1
  
positive.code: ;; (measurement-degree (make-measurement 1000 :m 3))
  ;; => 3
  
  ;; (measurement-magnitude (make-measurement-1 1000 :m 3))
  ;; => 1
  ;; (measurement-degree (make-measurement-1 1000 :m 3))
  
negative.code: ;; (measurement-degree (make-measurement-1 1 :m 3))
  ;; => 3
  
  ;; original:
  ;; (make-measurement-1 1000 :m 3)
  ;; => #<METER 1 Mm {1003FF93A3}>
  ;
  ;; (measurement-magnitude (make-measurement 1000 :m 3))
  ;; => 1000
  