Something educational.

How to determine if the mirror we're seeing is a real mirror or a 2-way mirror?


Just place the tip of your fingernail on the surface, and if there is a gap between your finger and the image, then it is a genuine mirror. If your fingernail touches directly the image of your nail, then it is a 2 way mirror.

Be careful girls, and guys too!

taken from: http://urbanlegends.about.com/od/crime/a/two_way_mirror.htm