he code for a character starts and

ends with a bar $($either narrow or wide$)$ and a $($white$)$ space appears between each bar.

The original specification $($since revised$)$ used exactly two wide bars and one wide

space in each character. For example, if b and B denote narrow and wide $($black$)$ bars,

respectively, and w and W denote narrow and wide $($white$)$ spaces, a valid character is

bwBwBWbwb $($the number $6).$ One character is held back as a start and stop delimiter.