Customizable corn sheller

Shelling corn is a chore done by hand in much of the rural developing world. Corn comes in different sizes - and the various [DIY shellers](https://www.engineeringforchange.org/news/2012/06/30/how_to_make_a_corn_sheller.html) are a major chore to make. Here you can either use the customizer app or the OpenSCAD to get the right size of sheller for your crop -- then print in plastic or metal.
This is an example of 3-D printable [open source appropriate technology](http://www.appropedia.org/images/0/0e/2012_case_for_OSAT.pdf) developed by [Michigan Tech's Open Sustainability Technology Lab](http://www.appropedia.org/Category:MOST).
This [academic paper](http://mtu.academia.edu/JoshuaPearce/Papers/1566597/3-D_Printing_of_Open_Source_Appropriate_Technologies_for_Self-Directed_Sustainable_Development) explains how 3-D printing could be a powerful tool for pulling people out of poverty in the developing world.