A crop circle in the form of a Triskelion composed of Circles:
This image has been (or is hereby) released into the public domain by its author, Alan L. Baughman. This applies worldwide.
In case this is not legally possible: Alan L. Baughman grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.
This image had been uploaded to the English wikipedia on 04:36, 5 Aug 2004 by en:User:Chris 73 (28516 bytes) (Crop circle). The original description is:
Source: FuturePropulsion: Though the original prototype has been patented, the material on the FuturePropulsion web site is not copyrighted. Please feel free to use any or all of it in any way you see fit. (Copyright notice).