As they entered theater, each took a pair of glasses and put them on.

"See, how they work," the first said, "is the right lens is polarized vertically and--"

"Wait, what do you mean by 'polarized'?" said the second.

"A vertically polarized lets no horizontally polarized light in, and a horizontally polarized lens lets no vertically polarized light in," said the third. "If two perpendicularly polarized lenses are put together, no light is let through."

"So as I was saying, the right lens is polarized vertically, and the left horizontally, or vice versa, such that each eye sees a different picture."

The second had an idea. "So that means if I..." He closed his right eye, and smiled. "Yes, I can only see your right eye."

The fourth and final person (you, of course), sensed something wrong. First, you verified the second's observation. Then, you said...

From what I remember from school physics, light can in fact not pass through two lenses with perpendicular polarization filters. Therefore when Mr. Second looks at Mr. First (both having their glasses on) I would expect that Mr. Second indeed sees only one of Mr. First's eyes. Only thing that could be wrong here is that Mr. Second should only see Mr. First's left eye (not his right) with his own left eye, because both have lenses with the same polarization. But that wouldn't make much of a puzzle.

Or the polarization filters work only in one direction, in which case you could still see both eyes of Mr. First with your glasses on. But I am not sure this is possible.

Edited on September 12, 2006, 1:05 pm

Posted by JLo on 2006-09-12 13:05:05