Braille pattern dots-138

The numbers identify positions, not a letter or the number 138.

Braille is a system of raised dots read by touch. Each group of dots is called a cell. In an eight-dot cell, the left column is numbered 1, 2, 3, 7 from top to bottom; the right is 4, 5, 6, 8. In ⢅, only positions 1, 3 and 8 are filled.

Unicode records that arrangement without assigning it a single reading. To translate it into ordinary text, you need the Braille code used for the document—the rules that match patterns to letters, numbers and other signs.

Why are there eight possible dots?

Eight positions allow 256 patterns; six allow 64, including blank cells.

Louis Braille published his six-dot system in 1829. Eight-dot systems also have a long history: Gabriel Abreu’s eight-dot music code was recognized by Spain’s Royal Conservatory in 1855.

Computer Braille uses the extra positions for more characters and screen information. By the late 1980s, eight-dot cells were common on electronic Braille displays, which form tactile text with pins that rise and fall.