Braille:

Braille is a technique for enabling blind and visually-impaired people to read and write. Refined in the late 1800's by Louis Braille for blind people, it was originally developed by a French army captain to enable officers to read battle commands without the aid of candle light hence revealing your position.

Each braille character or "cell" is made up of 6 dot positions, arranged in a rectangle comprising 2 columns of 3 dots each. A dot may be raised at any of the 6 positions, or any combination. Counting the space, in which no dots are raised, there are 64 such combinations. For reference purposes, a particular combination may be described by naming the positions where dots are raised; the positions being universally numbered 1 through 3 from top to bottom on the left and 4 through 6 from top to bottom on the right.

For example, dots 1-3-4 would describe a cell with three dots raised, at the top and bottom in the left column and on top of the right column. Because the 64 distinct characters are never enough to cover all possible print signs and their variations, it is necessary to use multi-character sequences for some purposes. Often this is accomplished by using certain characters as "prefixes" or "indicators" that affect the meaning of subsequent cells. For example, a dot 6 before a letter indicates that the letter is a capital, whereas otherwise it is understood to be lower case. For another example, dots 3-4-5-6, called the "numeric indicator", causes certain following letters (a through j) to be reinterpreted as digits.

Dot height, cell size and cell spacing are always uniform, and so many significant characteristics of the text, such as italics used for emphasis, must be handled by such indicators in Braille. An exception to that formatting, such as the centering of main headings, is commonly used in Braille in much the same way and for most of the same purposes as in print.

Separate braille codes may be used for notation systems other than natural languages such as music, mathematics and computer programming.

Partly because of the size that Braille pages occupy, and partly to improve the speed of writing and reading, the literary braille codes for English and many other languages employ "contractions" that substitute shorter sequences for the full spelling of commonly-occurring letter groups. For example, "the" is usually just one character in Braille. When contractions are used, the Braille is usually called "grade 2" in contrast to "grade 1" transcriptions where all words are spelled out letter-for-letter.

What does it look like?
Below is the layout of a Braille cell. It consists of two columns and three rows, with each dot read as "dot 1, dot 2, etc".

The Alphabet:
Each letter of the alphabet is listed below. Numbers are written by using the "a" as"1", "b" as "2", etc up to "j" as "0". Special symbols preceding a Braille cell indicate whether a number follows.