Martin the mind boggles, if you fix your gaze on one dot it never dissappears What is this testing you for ? & why does it work this way, ?. I have noticed that the print media is getting smaller & smaller & it should really be getting bigger as our eyesight deteriorates as we get older.They are on a continuous quest trying to squeeze a quart into a pint bottle. Some ads in Model Boats require a magnifying glass to read, I wonder who they think their customers are, Mick B.