anchor.diff:                                 name color alpha)))
   
   (defun context-add-box (context parent name tf dimensions &key
  +                                                           no-shadow
                                                               (color '(0 0 0))
                                                               (alpha 1d0)
                                                               (collision t)
                                                               (visual t))
     ;; Scene Graph
     (context-add-geometry context parent name tf (scene-box dimensions)
  +                        :no-shadow no-shadow
                           :color color :alpha alpha
                           :collision collision :visual visual)
     ;; Move It Scene
  
positive.code: 
  (defun context-add-cylinder (context parent name tf length radius axis
                               &key
                                 (color '(0 0 0))
                                 (alpha 1d0)
                                 (collision t)
                                 (visual t))
    ;; Scene Graph
    (context-add-geometry context parent name tf (robray::scene-cylinder length radius axis)
                          :color color :alpha alpha
                          :collision collision :visual visual)
    (when collision
  
negative.code: 
  (defun context-add-cone (context parent name tf length start-radius end-radius axis
                           &key
                             no-shadow
                             (color '(0 0 0))
                             (alpha 1d0)
                             (collision t)
                             (visual t))
    ;; Scene Graph
    (context-add-geometry context parent name tf (robray::scene-cone length start-radius end-radius axis)
                          :no-shadow no-shadow
                          :color color :alpha alpha
                          :collision collision :visual visual)
    (when collision
  