Braille designed a coding system, based on patterns of raised dots, which the blind could read by touch. Born on January 4, 1809, Coupvray, France, Braille was accidentally blinded in one eye at the age of three. Within two years, a disease in his other eye left him completely blind.

In 1819, Braille received a scholarship to the Institut National des Jeunes Aveugles (National Institute of Blind Youth), founded by Valentin Haüy (1745-1822). The same year Braille entered the school, Captain Charles Barbier invented sonography, or nightwriting, a system of embossed symbols used by soldiers to communicate silently at night on the battlefield. Inspired by a lecture Barbier gave at the Institute a few years later, the fifteen-year-old Braille adapted Barbier's system to replace Haüy's awkward embossed type, which he and his classmates had been obliged to learn.

In his initial study, Braille had experimented with geometric...