Paul Hsieh derivative license
The derivative content includes raw computer source code, ideas, opinions, and excerpts whose original source is covered under another license and transformations of such derivatives. Note that mere excerpts by themselves (with the exception of raw source code) are not considered derivative works under this license. Use and redistribution is limited to the following conditions:
One may not create a derivative work which, in any way, violates the Paul Hsieh exposition license described above on the original content.
One may not apply a license to a derivative work that precludes anyone else from using and redistributing derivative content.
One may not attribute any derivative content to authors not involved in the creation of the content, though an attribution to the author is not necessary.