Create a coin with Circular Gallifreyan text!
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 http://timeturners.wikidot.com/circular-gallifreyan for the language reference, and remember that not all letters are valid!