An attempt to generate a brilliant cut diamond shape based on info describing an ideal cut from folds.net/diamond_design/index.html
For something more easy to digest, have a look here secure.wikimedia.org/wikipedia/en/wiki/Brilliant_%28diamond_cut%29#Facet_proportions_and_names

Warning: This is just a simplified approximation of a brilliant cut, I am not a jeweller, but this should give you a good idea of size, shape and proportion. Most likely this shape will not print well without well calibrated support.

My code numbering scheme is as follows
Version_number < 1.0 not ready to be used by others
Version_number ==1.0 ready to be used provided you really know what you're doing
Version_number > 1.0 generally safe for use

To do:
- adjust the ratios for the extra 24 facets on top
- add ability to scale or specify a variable e.g. use provides height or diameter or carat weight
- Clean up code!
- Make printable

Changes:
0.4
- discovered relationship between circumscribed circle radii for 8 & 16 sided polygons needed for creating perfect facets along crown and pavillion is SinA+CosATanA where A=(360/16)/2=11.25
- second attempt to add 16 extra facets to crown and pavillion, using above relationship, more successful than previous attempt
- first attempt to add 8 extra facets to crown successful, using above relationship

0.3
- first attempt to add 16 extra facets to crown and pavillion, somewhat unsuccessful

0.2
- attempt to add 8 extra facets to crown and pavillion

0.1
- First attempt with 8 (9) faceted crown and pavillion on either side of cylindrical girdle