Are you familiar with 3D glasses? Perhaps when you were younger you had an experience of watching movies at your local theater or Dryden — many people don’t know that these types of glasses are actually manufactured in two different formats today — 1 model makes use of lenses which are manufactured from two different colors (blue and red). The other type of glasses are manufactured using green and red colored lenses. These different types of lenses are available because there are different processes used to manufacture the 3-D movies. I’m sure that most kids don’t really care — they just enjoy seeing the movie!