When Linux gets inspired by Mac OS X - Yoc - 02:43:28
"...But the biggest surprise is the new graphic interface which uses OpenGL
to create effects which you are all too familiar with, like window
transparency, switching desktops using a large rotating cube, or creating a
thumbnail view of a window."
Videos included as well. I can't say I agree with the article (e.g.
http://freshmeat.net/projects/3ddesktop/ predates it), but it's worth a
read. It's very short too.