The font file is already upload,you can get it from
http://www.geocities.com/larc01trick/illusion.html
I enable the function (GRAYS_USE_GAMMA ) in ftgray.c ,
but enable this function isn't recommend by author.
Actually, i don't want to use this function to adjust the gamma value.
For freetype development
http://www.acad.polyu.edu.hk/~lbdennis/hifi/patch/rpm/dev/freetype-2.1.4-7ug.src.rpm