During World War II, the Aldis lamp was used with valuable results. It was a signaling lamp with a special feature. When flashed from a ship, it could be seen only by someone standing within a certain stretch of the shoreline. Anyone standing too far on either side of the stretch could not see it. but anyone wanting to catch the message needed only change his viewpoint.
Not happy with your results change your view ever so slightly, you might surprise yourself.
Trader
Not happy with your results change your view ever so slightly, you might surprise yourself.
Trader

