Eight-dot Braille

There are numerous examples, both historic and modern, in which the six dots of the traditional braille cell have proven inadequate for a particular task. Enterprising inventors, teachers, and braille users have sought to expand the possibilities of the braille cell by increasing the number of dots from six to eight. These expansions have resulted in a cell that is two dots wide and four dots high. Instead of the 63 possible dot combinations in a six-dot cell, an eight-dot cell yields 255 possible dot combinations. Typically, the dots of the eight-dot braille cell are numbered 1, 2, 3, 7 downward on the left and 4, 5, 6, 8 downward on the right.