Louis Braille became blind aged three. In 1821 he started to devise the Braille system to help people with visual impairments to read and write…

Invented by Louis Braille at the age of 15, the idea came from a soldier who had served in the Napoleonic army in Poland and had attempted to devise a system that could, with night-time manoeuvres, allow messages to be sent and instructions to be passed from hand to hand.

It didn’t work, because the system was too complex and the soldiers didn’t get it. Not surprisingly, because to read Braille without being able to see you need to develop sensitive finger ends.