Please note that as of October 24, 2014, the Nokia Developer Wiki will no longer be accepting user contributions, including new entries, edits and comments, as we begin transitioning to our new home, in the Windows Phone Development Wiki. We plan to move over the majority of the existing entries. Thanks for all your past and future contributions.
The braille system was invented by Louis Braille in 1821. It's commonly used by blind people to read and write. Braille characters are embossed as points that can be felt with your fingertips.
More info in Wikipedia