The font must not contain any symbols which at the font creation time already have a meaning. This font is not intended to exclude the decimal numeration and its representation from use ! Decimal numeration have important basis/sense, and must never be excluded. The font primary intension. Give a separate character set, which can represent a machine data, and lets to read it. Not including/interacting/overlapping known/existing character sets, like Arabic numeral (decimal digits) and English alphabet characters.