...can be the next development,for a simple structure rolling as in a "wind".
This time the rolling motion is on the "spot",but makes as if moves away.
You can see the design at: www.geocities.com/iacob_alex/Some_Drafts/text015.jpg
The horizontal track/line is replaced by a rotating, smaller driven follower...but with two is better(see car's wheel test),we gain some stability.
The evolution of the energetic process is a natural one : long charge-short discharge.
All the Bests! / Alex