Louis Braille, of France, was blinded in a childhood accident.
At the age of 15 he modified a failed military system for reading orders at night without showing any light (night writing), inventing Braille.
Braille is a tactile writing system used by blind people.
Braille's system is easier to read compared to night writing and some of its raised-dot competitors in that each symbol fits at once underneath the fingertip.
Braille also gave blind users the ability to write, a great improvement over embossed letter systems.
Braille is also notable for being a binary code that predated the invention of the computer.

Dot height is approximately 0.5 mm; the horizontal and vertical spacing between dot centers within a braille cell is approximately 2.5 mm; the blank space between dots on adjacent cells is approximately (3.75 mm horizontally and 5.0 mm vertically.
A standard braille page is 11 inches by 11 inches and typically has a maximum of 40 to 42 braille cells per line and 25 lines.
Braille may be produced using a "slate" and a "stylus" in which each dot is created from the back of the page, writing in mirror image, by hand, or it may be produced on a braille typewriter or "Perkins Brailler", or produced by a Braille Embosser attached to a computer.