anchor.diff:  (defun descendant-p (maybe-descendant ancestor)
     (ancestor-p ancestor maybe-descendant))
   
  -
   ;;;
   ;;; Property Access
   ;;;
  +
   (define-condition unbound-property (sheeple-error)
     ())
   (define-condition locked-property (sheeple-error)
  
positive.code: ;; * Add property option that works like :initform
  ;; * Add clone option to copy individual properties?
  ;; * Add property option that forces all descendants to copy a property
  ;; * Write tests for locked-property-related stuff.
  ;; * Clone option to auto-generate all accessors (with optional appending a-la defstruct?)
  ;; * Write more unit tests
  ;; * Keep cleaning and testing until it's stable
  ;; * Documentation!!
  ;;
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  
negative.code: (defmethod print-object ((sheep standard-sheep) stream)
    (print-unreadable-object (sheep stream :identity t)
      (format stream "Standard Sheep SID: ~a~@[ AKA: ~a~]" (sid sheep) (sheep-nickname sheep))))
  
  ;;;
  ;;; Sheep creation
  ;;;
  