anchor.diff:    (html-out
       (draw-gradients color)
       (:circle :class "donut-hole" :cx *ring-cx* :cy *ring-cy* :r *ring-r*
  -             :fill "url(#grad1)")))
  +             :fill "url(#grad1)")
  +    ;;spectral highlight
  +    (:ellipse :fill "url(#grad2)" :style "opacity:0.8;" :fill-opacity "1"
  +              :cx "19.5" :cy "14.0" :rx "8.68" :ry "8.36")))
   
   (defun intervals (num)
     (unless (zerop num)
  
positive.code: (defparameter *ring-cy* "21")
  (defparameter *ring-r* "15.91549430918954")
  
  (defmethod convert-tag-to-string-list ((tag (eql :radialgradient))
                                         attr-list body body-fn)
    (nconc (cons "<radialGradient"
  
negative.code:          (funcall body-fn body)
           (list "</radialGradient>")))
  
  (defun draw-gradients (color)
    (html-out
      (:defs
          (:radialGradient
           :id "grad1" ;:cy *ring-cy*
           ;;:fx "10%" :fy "50%" :r "8"
           :fx "50%" :fy "30%" :r "1"
           (:stop :offset "0%" :stop-color color)
           (:stop
            :offset "100%"
            :stop-color (simple-rgb:xmlify-rgb
                         (simple-rgb:darken-rgb
                          (simple-rgb::parse color) :alpha 0.75))))
          (:radialGradient
           :id "grad2" :cx "21" :cy "10.5"
           :fx "21" :fy "10.5" :r "5.08"
           :|gradientTransform| "matrix(1.66,0.04,-0.03,1.25, -15.43,-0.099)"
           :|gradientUnits| "userSpaceOnUse"
           (:stop :offset "0%" :stop-color "#fff" :stop-opacity "1")
           (:stop :offset "100%" :stop-color "#fff" :stop-opacity "0")))))
  
  (defun draw-ring (hole-func content-func)
    (html-out
  