I would like to know why it didn't work it should, shouldn't it?

I dont know if animate graphics work at all as the desktop. I tried it and
nothing happened. I dont think the desktop has the ability to run animation
without some help application.ubuntuforums.org/showthread.php?p=5223621This thread in the forums seems to state - back and forth - that you can do it
but you lose some desktop functionality. I dont know if its worth the overall
trouble.

Now a different approach is to rotate your desktop ever 5 minutes or so giving
you a different desktop. But as for animation - you'll have to make the call as
to how you want to approach it and what you are willing to give up.