Ok.. so it took me some time to figure out that I needed to play with the Master Shader in the animation timeline, to get the animation to repeat more than the 1 second that the actual animation lasts.

Attaching a screenshot for those who may also want to follow what I did.

So the next question is, when I tried to add the spin modifier, it spins too fast and I havent been able to figure out how to slow it down.  I tried playing with the "Cycles per second"  setting, but all I manged to do, was make the cube spin faster and even change directions.