Customizable egg

Ridiculously over-engineered way to create a chicken egg.

You can create either by size (inches, mm, whatever) or actual USDA size rating.

Some potential uses are:
* subtract it for egg cups or egg holders
* print eggs for your broody hens to sit on
* a stand-in when building an egg-bot
* Easter decoration

More details over at my projects blog, here:
https://theheadlesssourceman.wordpress.com/2017/12/31/customizable-egg/