Some liberties were taken with the writing style, as laying out the lines would have required much more complicated logic.

If you have a lot of letters, you'll need increase 'pendant_radius' or decrease 'letter_radius'. Some value combinations cause openscad to barf, so try changing them slightly.

See timeturners.wikidot.com/circular-gallifreyan for the language reference, and remember that not all letters are valid!