A remix of http://www.openclipart.org/detail/631 originally derived from the US government EPA "Sunwise" program. I converted it from PDF format. the source link is here - http://www.epa.gov/sunwise/doc/poster.pdf
There is more detail on the doors.
This image was donated by Pearson Scott Foresman, an educational publisher, to Wikimedia Commons, and is thereby in the Public Domain.
---
See http://commons.wikimedia.org/wiki/Category:Pearson_Scott_Foresman_publisher
an image from the US government EPA "Sunwise" program. I converted it from PDF format. the source link is here - http://www.epa.gov/sunwise/doc/poster.pdf
A sketch I made from scratch with a wireless mouse to begin building a logo that rivals the chic silhouetted fruit logo of a certain company...
If imitation of the FSF GNU head is infringement, I guess I will be removed but we will see how it goes.