have you ever heared of "Anil K. Gupta"? He collects inventions from the poorest of the poorest people in India and help them to get some return.
Please have a look his TED Talk:
E.g. at 12:34 he presents a clay pan! Because of the video of P. Wheaton video about the cast iron skillet I remembered Anil G. video about inventions.
So imagine you have a clay pit on your property and an mass rocket heater which you can burn the clay maybe your clay are able to make such clay pans!? Or
something better (http://www.sristi.org/hbnew/honeybee_innovation.php)!
The video is mind blowing to me what a blast to see all this genius people please have a look and imporve the ideas or adapt it to your inventions... limitation
leads to better designs a permaculture principle . A database of inventions: http://www.nif.org.in/bd/product_catalog/cv great stuff.