Hanggliders fly in the background of the X screen.
You can build and run this program if you have C
compiler, include files like Xlib.h, and X is available.

I recommend 8bpp or more.

For me, I like to run the program with options "-pilot
4 -vario -frequency 0.2", without the option
'-noflicker' or '-useclip'. It is much faster!
