If R3 is set to 5 instead of 6 or more, then the frame is shifted to the right on the CTM monitor with an offset of half a CRTC character. This is due to the effect of shortening the C-HSYNC produced by the [[Gate Array]].
Even further, continuously switching these values between each raster line, instead of once per frame, will divide by 2 the difference between the 2 positions and so will give an offset of a quarter of a CRTC character.
As these effects rely on invalid video signals, they are badly supported on modern displays.