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.
