Ping-Pong CD Solar Concentrator

Look at the title of this post, understood anything? The last two words are okay but got any guess whats that pingy pongy stuff. Well, let your inner curious feeling read the rest of the post to satisfy itself.

Ping-Pong CD Concentrator is an idea that flashed into my mind when I saw the shiny side of a pile of useless CDs & DVDs lying on my desktop. The ping-pong element comes from a common plastic ping pong ball thats used to play table tennis. I was a table tennis player in school.
So, imagine a CD placed on a ping pong ball with shiny side up. Ball fits into the hole in centre of CD and if you fix the ball there, what you get is a kind of rotating mirror which can rotate 2 sides either right-left or front-back. Lets visualise it;
http://sunenergyworld.blogspot.com/2006/10/ping-pong-cd-solar-concentrator.html