Metisse is an experimental X desktop with neat OpenGL features.  It consists
of a virtual X server called Xmetisse, a special version of FVWM, and a FVWM
module FvwmCompositor.

Metisse was designed with two goals in mind.  First, it should make it easy
for HCI researchers to design and implement innovative window management
techniques.  Second, it should conform to existing standards and be robust
and efficient enough to be used on a daily basis, making a suitable platform
for the evaluation of the proposed techniques.

WWW: http://insitu.lri.fr/metisse/