Here are two sketches that demonstrate how permaculture can be a useful tool to explain and design human systems:

This upper one is depicting the current human process for creating a cup of tea.
The result under the current system is: waste, pollution, energy loss, and destruction of nature.

Next is a drawing showing the creation of one cup of tea using permaculture principles.
Much less energy is used and outputs can be recycled directly back into the earth.

Through understanding and proper design we can mitigate the effects of current infrastructure and create healthy systems to fill our needs.

 
(scetches are borrowed from  'Permaculture: A Beginners Guide' by Graham Burnett)

permaculture links
'essence of permaculture' / download it here