Which of the following examples connected with colors hasn’ t been mentioned in the talk?

Today, I’ d like to talk about colors. For a person with normal vision, color plays such important role in decorating their lives. Beside personal life, color is thought to be useful in many cases. For example, on a driving license in some Western countries, the driver’ s hair color and eye color should be written clearly so as to identify the driver. In many countries, trains and subways are painted in different colors to show one line is different from another. Telephones are made in different colors for particular uses. Besides, in the international games, the color of a country’ s flag is a big help as well in telling one nation from another. What’ s more, some psychologists have studied the connection between colors and human emotions, and personalities. With more vivid uses of different colors, we can hardly imagine a less colorful world. We also have every reason to believe that modern technology will pass the related color information to those visually handicapped people so that they can better enjoy the colorful life.