anchor.diff:                               x z y)))))
   
   (defmethod print-object ((object pov-matrix) stream)
  -  (let ((elements (pov-matrix-elements object)))
  -    (with-pov-indent old-indent
  +  (let ((elements (pov-matrix-elements object))
  +        (old-indent *pov-indent*))
  +    (with-pov-indent
         (format stream "~&~Amatrix <~&~A~F, ~F, ~F,~&~A~F, ~F, ~F,~&~A~F, ~F, ~F,~&~A~F, ~F, ~F~&~A>"
                 old-indent
                 *pov-indent*
  
positive.code:   value)
  
  (defmethod print-object ((object pov-version) stream)
    (with-pov-indent old-indent
      (declare (ignore old-indent))
      (format stream "~&#version ~A;"
              (pov-version-value object))))
  
  
negative.code:   else)
  
  (defmethod print-object ((object pov-switch) stream)
    (with-pov-indent
      (format stream "~&#switch (~A) ~{~A~}~@[~A~]~&#end"
              (pov-switch-value object)
              (pov-switch-clauses object)
  