anchor.diff:                 :documentation "List of everyone who lives in the town, marked by their clothing choice.")
      (styles :initarg :styles
              :accessor styles
  -           :documentation "Available styles. Styles are always represented by characters.")
  -   (hipsterish-tendency :initarg :hipsterish-tendency
  -                        :accessor hipsterish-tendency
  -                        :documentation "How likely would any individual be nonconformist at any given time."))
  +           :documentation "Available styles. Styles are always represented by characters."))
     (:documentation "A hipster town at a particular time."))
   
   (defclass delayed-town (town-snapshot)
  
positive.code:   (when (numberp styles)
      (setf styles (subseq *style-character-list* 0 styles)))
    (make-instance 'foggy-town
                   :population (generate-random-town population styles volatile)
                   :visibility visibility
                   :hipsterish-tendency hipsterish-tendency
                   :styles styles))
  
  ;;; Common class methods
  
  (defmethod print-object ((object town-snapshot) stream)
    (with-accessors ((ticks ticks) (population population) (tendency hipsterish-tendency) (styles styles)) object
      (print-unreadable-object (object stream :type t)
        (format stream ":~:[~;VOLATILE-~]POPULATION ~a :TENDENCY ~4,2f% :STYLES ~a @ t = ~a"
                (adjustable-array-p population) (length population) (* tendency 100) (length styles) ticks))))
  
  (defmethod print-object ((object delayed-town) stream)
    (with-accessors ((ticks ticks) (population population) (tendency hipsterish-tendency) (styles styles) (period period)) object
      (print-unreadable-object (object stream :type t)
        (format stream ":~:[~;VOLATILE-~]POPULATION ~a :TENDENCY ~4,2f% :STYLES ~a :DELAY ~a @ t = ~a"
                (adjustable-array-p population) (length population) (* tendency 100) (length styles) period ticks))))
  
  (defmethod print-object ((object foggy-town) stream)
    (with-accessors ((ticks ticks) (population population) (tendency hipsterish-tendency) (styles styles) (visibility visibility)) object
      (print-unreadable-object (object stream :type t)
        (format stream ":~:[~;VOLATILE-~]POPULATION ~a :TENDENCY ~4,2f% :STYLES ~a :VISIBILITY ~a @ t = ~a"
                (adjustable-array-p population) (length population) (* tendency 100) (length styles) visibility ticks))))
  
  (defmethod print-object ((object inhabitant) stream)
    (with-accessors ((type inhabitant-type) (tendency hipsterish-tendency) (styles styles)) object
  
negative.code:   (when (numberp styles)
      (setf styles (subseq *style-character-list* 0 styles)))
    (make-instance 'town-snapshot
                   :population (generate-random-town population styles volatile hipsterish-tendency)
                   :styles styles))
  
  (defun make-delayed-town (population period &key (hipsterish-tendency 2/3) (styles #(#\# #\.)) volatile)
    (when (numberp styles)
      (setf styles (subseq *style-character-list* 0 styles)))
    (make-instance 'delayed-town
                   :population (generate-random-town population styles volatile hipsterish-tendency)
                   :period period
                   :history (make-array (list period population) :adjustable volatile :initial-element nil)
                   :styles styles))
  
  (defmethod initialize-instance :after ((instance delayed-town) &key)
  