anchor.diff:    (declare (optimize (speed 3) (safety 1) (debug 1)))
     (let ((s-a (sin angle))
           (c-a (cos angle)))
  -    (set-components 1f0  0f0  0f0     0f0
  +    (set-components 1f0  0f0  0f0        0f0
                       0f0  c-a  (cl:- s-a) 0f0
  -                    0f0  s-a  c-a     0f0
  -                    0f0  0f0  0f0     1f0
  +                    0f0  s-a  c-a        0f0
  +                    0f0  0f0  0f0        1f0
                       mat-to-mutate)))
   
   ;;----------------------------------------------------------------
  
positive.code:   (declare (optimize (speed 3) (safety 1) (debug 1)))
    (let ((s-a (sin angle))
          (c-a (cos angle)))
      (set-components c-a      0f0  s-a  0f0
                      0f0      1f0  0f0  0f0
                      (cl:- s-a)  0f0  c-a  0f0
                      0f0      0f0  0f0  1f0
                      mat-to-mutate)))
  
  ;;----------------------------------------------------------------
  
negative.code: (defn set-from-scale ((mat-to-mutate mat4) (scale-vec3 vec3)) mat4
    (declare (optimize (speed 3) (safety 1) (debug 1)))
    (set-components
     (x scale-vec3)    0f0               0f0               0f0
     0f0               (y scale-vec3)    0f0               0f0
     0f0               0f0               (z scale-vec3)    0f0
     0f0               0f0               0f0               1f0
     mat-to-mutate))
  
  