anchor.diff:                 ;; TODO: assumed uv mapping
                  (push (pov-value "uv_mapping") pigments))
                 (otherwise (error "Unknown texture property: ~A" (cons property value))))))
  -    (pov-texture (append (when pigments
  -                           (list (pov-pigment pigments)))
  -                         (when finishes
  -                           (list (pov-finish finishes)))))))
  +    (pov-texture (nconc (when pigments
  +                          (list (pov-pigment pigments)))
  +                        (when finishes
  +                          (list (pov-finish finishes)))))))
   
   
   (defstruct (pov-version (:constructor pov-version (value)))
  
positive.code:                (push (pov-item name finish) finishes))
               (add-pigment (name pigment)
                 (unless has-image-map
                   (push (pov-item name pigment) pigments))))
        (loop for (property . value) in alist
           do (case property
                (:ambient
  
negative.code:                (when (and (or (listp value)
                                (vectorp value))
                            (not (assoc :color alist)))
                   (alpha)
                   (add-pigment "color" (pov-rgb value))))
                (:alpha) ;; handled in color case
                (:color
                 (alpha)
                 (add-pigment "color" (pov-rgb value)))
                (:specular
                 (add-finish "specular" (avg-rgb value)))
                (:index-of-refraction ; TODO
  