I look forward to seeing the book.

Your methods seem a lot more likely and workable to of than a big frame with a rock on a rope.

It's sort of how I pictured it when I saw the reconstruction of the a-frame experiment. It all just seemed too cumbersome and random.

Individual rock-on-a-rope seems much more sensible to me. And much more portable.

But, I suppose as with all of these things - you'd use the best method for the job, so maybe a combination of all of the above :)

G x