anchor.diff:  
   ;;------------------------------------------------------------
   
  -(defun draw-tex-top-left (sampler/tex &optional (flip-uvs-vertically t))
  +(defun draw-tex-top-left (sampler/tex &key (flip-uvs-vertically nil))
     (draw-tex-tl sampler/tex flip-uvs-vertically))
   
  -(defmethod draw-tex-tl ((sampler sampler) &optional (flip-uvs-vertically t))
  +(defmethod draw-tex-tl ((sampler sampler) &key (flip-uvs-vertically nil))
     (if (eq (sampler-type sampler) :sampler-cube)
         (%draw-cube-face sampler (v! -0.5 0.5) 1.5707 0.5)
         (%draw-sampler sampler (v! -0.5 0.5) 0s0 0.5 flip-uvs-vertically)))
   
   ;;------------------------------------------------------------
   
  -(defun draw-tex-bottom-left (sampler/tex &optional (flip-uvs-vertically t))
  -  (draw-tex-bl sampler/tex flip-uvs-vertically))
  -
  -(defmethod draw-tex-bl ((sampler sampler) &optional (flip-uvs-vertically t))
  +(defun draw-tex-bottom-left (sampler/tex &key (flip-uvs-vertically nil))
  +  (draw-tex-bl sampler/tex :flip-uvs-vertically flip-uvs-vertically))
  +
  +(defmethod draw-tex-bl ((sampler sampler) &key (flip-uvs-vertically nil))
     (if (eq (sampler-type sampler) :sampler-cube)
         (%draw-cube-face sampler (v! -0.5 -0.5) 1.5707 0.5)
         (%draw-sampler sampler (v! -0.5 -0.5) 0s0 0.5 flip-uvs-vertically)))
   
   ;;------------------------------------------------------------
   
  -(defun draw-tex-top-right (sampler/tex &optional (flip-uvs-vertically t))
  -  (draw-tex-tr sampler/tex flip-uvs-vertically))
  -
  -(defmethod draw-tex-tr ((sampler sampler) &optional (flip-uvs-vertically t))
  +(defun draw-tex-top-right (sampler/tex &key (flip-uvs-vertically nil))
  +  (draw-tex-tr sampler/tex :flip-uvs-vertically flip-uvs-vertically))
  +
  +(defmethod draw-tex-tr ((sampler sampler) &key (flip-uvs-vertically nil))
     (if (eq (sampler-type sampler) :sampler-cube)
         (%draw-cube-face sampler (v! 0.5 0.5) 1.5707 0.5)
         (%draw-sampler sampler (v! 0.5 0.5) 0s0 0.5 flip-uvs-vertically)))
   
   ;;------------------------------------------------------------
   
  -(defun draw-tex-bottom-right (sampler/tex &optional (flip-uvs-vertically t))
  -  (draw-tex-br sampler/tex flip-uvs-vertically))
  -
  -(defmethod draw-tex-br ((sampler sampler) &optional (flip-uvs-vertically t))
  +(defun draw-tex-bottom-right (sampler/tex &key (flip-uvs-vertically nil))
  +  (draw-tex-br sampler/tex :flip-uvs-vertically flip-uvs-vertically))
  +
  +(defmethod draw-tex-br ((sampler sampler) &key (flip-uvs-vertically nil))
     (if (eq (sampler-type sampler) :sampler-cube)
         (%draw-cube-face sampler (v! 0.5 -0.5) 1.5707 0.5)
         (%draw-sampler sampler (v! 0.5 -0.5) 0s0 0.5 flip-uvs-vertically)))
  
positive.code:     (map-g #'draw-texture-pipeline (get-gpu-quad)
             :tex sampler
             :transform transform
             :uv-y-mult (if flip-uvs-vertically -1s0 1s0))))
  
  (defun rotated-rect-size (size-v2 φ)
    ;; returns width & height
  
negative.code: ;;------------------------------------------------------------
  
  (defmethod draw-tex ((tex texture)
                       &key (scale 0.9) (flip-uvs-vertically nil))
    (with-sampling (s tex)
      (draw-tex s :scale scale :flip-uvs-vertically flip-uvs-vertically)))
  
  (defmethod draw-tex ((sampler sampler)
                       &key (scale 0.9) (flip-uvs-vertically nil))
    (cepl-utils:with-setf (depth-test-function *cepl-context*) nil
      (if (eq (sampler-type sampler) :sampler-cube)
          (%draw-cube-face sampler (v! -0 0) 1.5707 scale)
  