Six-dot braille cell

The usual braille cell has six dot positions arranged in two columns and three rows. We traditionally number these dot positions from one to six:

1. Top row, left-hand column
2. Middle row, left-hand column
3. Bottom row, left-hand column
4. Top row, right-hand column
5. Middle row, right-hand column
6. Bottom row, right-hand column

A dot can be either present or absent in each dot position. A cell with six dot positions gives 64 different characters, because 2 raised to the power 6 is 64.

We can represent a braille character in words by listing the numbers of the dot positions where dots are present. For example, we can refer to a braille character that has dots in dot positions 1 and 5 as "dots 1 5" or "dots 1-5" or, slightly more concisely, as "dots 15", all of which we read as "dots one five".