What is the Braille system and in what way it helps visually challenged persons? Explain in details.

The most popular resource for visually challenged persons is Braille. The Braille system was developed by Louis Braille. He himself was a visually challenged person. There is Braille code for common languages, mathematics and scientific notation. Many Indian languages can be read using the Braille system.
The Braille system has 63 dot patterns or characters. Each character represents a letter, a combination of letters, a common word or a grammatical sign. Dots are arranged in cells of two vertical rows of three dots each. Patterns of dots to represent some English letters and some common words are shown in the below given figure.
These patterns, when embossed on Braille sheets, help visually challenged persons to recognise words by touching. To make them easier to touch, the dots are raised slightly.
Visually challenged people learn the Braille system by beginning with letters, then special characters and letter combinations. Methods depend upon recognition by touching. Each character has to be memorised. Braille texts can be produced by hand or by machine. Typewriter-like devices and printing machines have now been developed.