Feisty Fawn - cube effects suddenly missing

I run Feisty Fawn (Ubuntu 7.04) on one of my Linux boxes. I have enabled desktop effects (System > Preferences > Desktop effects). A few times I have had problems with the rotating cube, i.e. I am not able to rotate the cube. The wobbly windows are working fine.

In order to fix this issue, start gconf-editor (e.g by pressing Alt+F2 and writing gconf-editor or running it from the terminal). Go to "apps" > "compiz" > "general" > "screen0" > "options" and make sure that "hsize" is set to 4 (mine is usually set to 1 when the cube isn't working). Now, the rotating cube should work fine again.