A fraction written out in Nemeth Braille Code (brailleauthority.org)

One night in the late 1940s, Abraham Nemeth was helping some World War II vets with their calculus studies when he went up to the blackboard to work out a problem.

Now this may not seem remarkable, but Nemeth was blind, and a blackboard is, well, flat. Notwithstanding, Nemeth later recalled that he didn't find writing on the blackboard difficult. Little did he know the chairman of the math department was watching carefully, and was impressed with Nemeth's math skills. Soon thereafter, Nemeth says, "I received a telegram from him asking if I could replace a member of the math faculty who was ill. The telegram asked if I could start next Monday. I said yes."

As a math instructor, Nemeth found that he needed a way to take notes that he could later read. The system in use at the time, the Taylor Code, "used too many grouping symbols," in Nemeth's view. Nemeth already had developed a system for reading math out loud, and he set about creating a Braille system that mimicked the spoken math. He explained it in a 1991 interview:

For example, when you say “x to the n power,” the phrase “to the” means “begin a superscript,” and the word “power” means “return to the baseline.” So in my Braille code I created symbols that mean “begin superscript” and “return to the baseline.” My personal code for Braille mathematics began to evolve. I used it for my work in calculus and statistics.

That code, today known as the Nemeth Code, has been instrumental in opening up careers in science and math to people who are blind or have other visual impairments. According to the National Federation of the Blind, the man who gave the world this code has now passed away, two weeks short of his 95th birthday.