Braille: Braille is one of the most widely used braille systems. It uses raised lattice to represent letters, numbers, punctuation marks and some commonly used abbreviations. Braille was first invented by the French blind Louis Braille, and now it has become the main reading and writing method for the blind in many countries in the world.

Nemeth code: Mathematical Braille is a Braille system for reading and writing mathematical symbols. It was invented by American educator Abraham nemeth in 1952 to describe various mathematical symbols, including mathematical operators, relational operators, fractions, exponents and so on.

Chemical Braille: Chemical Braille is a Braille system for reading and writing chemical symbols. It was invented by Czech chemist Alfred Julius Gardner in 1922 to describe various chemical symbols, including elemental symbols, molecular structures, chemical equations and so on. The symbols in chemical braille are all expressed in the form of dot matrix.