That's just it. It's a metaphor, and in fact largely relies on visualization metaphors (strings, laser beams, flowing water, etc...) as part of the training. I think these kind of metaphors can be very useful IN Aikido practice. That is, while one is doing a technique or movement one may be able to use the thought images as a guide to learning the proper movement patterns. Since the endpoint is the ability to have such patterns stored and accessed in an unconscious part of the brain, whatever can be used as a stepping stone is valid. However, my qualm is with spending a lot of time doing Ki games and parlor tricks INSTEAD of doing actual, physical Aikido training. From what I've seen in the Ki Society books and seen and heard from a couple of former students, it also sounds like this is done in a context where the purportedly amazing results of these trick are used to proselytize superstitions about the 'realities' of Ki. To me, this sounds like a waste of time, at best, and something inimical to my beliefs as a person and ethics as a trainer, at worst.