Re: How do Lenticular lenses work?

From the site that you mention, they say that
"A lenticular lens screen is a flat sheet of plastic the surface of which is 
embossed with an array of parallel cylindrical lens (elongated lenses).  An 
individual lens is called a lenticule.  Each lenticule has a focal length equal 
to the thickness of the sheet.  Each lenticule magnifies a very narrow strip 
(i.e. 1/36th  the width of a lenticule) of whatever is on the opposite side of 
the sheet.  One lenticule therefore can show one of 36 different strips 
depending on your angle of view."

I'm sure you have seen these devices.  I have heard them called "flip 
image pictures".  The picture changes as you tilt it.  And, as it says in the 
site's description, the lens itself is an array of narrow cylindrical lenses 
that allows you to see only a thin strip at a time of whatever is behind it.

John Link, MadSci Physicist