I have no idea why but Ubuntu doesn't allow to configure the screensavers itcomes with. Not those screensavers were not configurable, but in contrast toxscreensaver-demo, Ubuntu itselfdoes not offer access to their visual config :-( What I wanted to do is stopGLMatrix from rotating the matrix, which would have been -no-rotate on thecommand line. Editing glmatrix.desktop in/usr/share/applications/screensavers finally helped: