Bob Haselby contributed >This sounds like a "signal mirror" which were also contained in life >jackets etc as survival gear. The more modern are quite effective >and are great for annoying people on the beach. It uses double internal >reflection in the hole to give a virtual image of the sun
Any chance of a diagram or somesuch to show how this works Bob? - I understand 'total internal reflection' but 'double internal reflection" err! yes!! err!! I should have paid more attention in Physics instead of yearning for the workshop! Tony Moss
