anchor.diff:    "Returns a matrix which would rotate a point around the y axis
      by the specified amount"
     (declare (single-float angle))
  -  (let ((c-a (cos angle))
  -        (s-a (sin angle)))
  -    (make-matrix3 c-a    0.0    (- s-a)
  -                  0.0    1.0    0.0
  -                  s-a    0.0    c-a)))
  +  (let ((s-a (sin angle))
  +        (c-a (cos angle)))
  +    (make-matrix3 c-a      0.0    s-a
  +                  0.0      1.0    0.0
  +                  (- s-a)  0.0    c-a)))
   
   ;;----------------------------------------------------------------
   
  
positive.code:   "Returns a matrix which would rotate a point around the x axis
     by the specified amount"
    (declare (single-float angle))
    (let ((c-a (cos angle))
          (s-a (sin angle)))
      (make-matrix3 1.0    0.0       0.0
                    0.0    c-a       s-a
                    0.0    (- s-a)   c-a)))
  
  ;;----------------------------------------------------------------
  
  
negative.code:   "Returns a matrix which would rotate a point around the z axis
     by the specified amount"
    (declare (single-float angle))
    (let ((s-a (sin angle))
          (c-a (cos angle)))
      (make-matrix3 c-a  (- s-a)  0.0
                    s-a  c-a      0.0
                    0.0  0.0      1.0)))
  
  ;;----------------------------------------------------------------
  
  