The Fast Light Tool Kit ("FLTK", pronounced "fulltick") is a LGPL'd
C++ graphical user interface toolkit for X (UNIX(r)), OpenGL(r),
and Microsoft(r) Windows(r) NT 4.0, 95, or 98. It was originally
developed by Mr. Bill Spitzak and is currently maintained by a
small group of developers across the world with a central
repository in the US.