Braille is a medium which allows a to read a text by touch, without seeing it., and can be used by scientists in experiments, requiring the total darkness. In contrast to popular belief, Braille is character encoding rather than language; text of any language can be encoded in Braille.
Each Braille character (cell) is made up of six dot positions, arranged in a 2 x 3 rectangle. This allows to encode 26 combinations, but some of these represent the same pattern just shifted inside the cell. Patterns that only differ by they position inside the cell feel too similar in touch, and only one of them can be used. Braille cell is small enough for the human finger can encompass the whole symbol without moving, and can not move rapidly from one symbol to another while reading. Braille can be seen as the world's first binary encoding scheme for representing the characters.
Braille characters are larger than their printed equivalents. To reduce space and increase reading speed, Braille books are transcribed in what is known as Grade 2 Braille, which uses a system of contractions to reduce space and speed the process of reading. A competent writer of Braille has a speed advantage over the person who writes in conventional text, whether hand-written or typed, since using Braille is faster than either of them.