This was posted on Focusfusion.org forum.
I think it is the very first video with logical explanations about poorly understood energy phenomena.
Worth the whole 3.5 min of it: http://www.youtube.com/watch?v=A25FRpkbDxU
Video is self explanatory. No comments are needed.
Very straight forward demonstration, and the assumptions are clearly stated, and the engineering and scaling issues addressed.
And, they allowed us to see inside their black box!