anchor.diff:  				       (vc-b vector-b)) 3
       (* vc-a vc-b)))
   
  -;----------------------------------------------------------------
  +;;---------------------------------------------------------------
   
   ;;; may just be an evil side effect of ripping this off from
   ;;; from ogre but some of the optomisations will be coming over
  
positive.code:   (float-zero (apply-across-elements + ((vc-a vector-a)) 3
  		   (expt vc-a 2))))
  
  ;----------------------------------------------------------------
  
  (declaim (inline unitp)
  	 (ftype (function ((simple-array single-float (3))) 
  
negative.code:    a new vector4"
    (reduce #'v-1 vec3s))
  
  ;;---------------------------------------------------------------
  
  (declaim (inline v-1)
  	 (ftype (function ((simple-array single-float (3)) 
  