Yes, I've heard of your (in)famous yaw strings. That's good physics you had going on there with static electricity and cycling!

It was made of the normal yellow polypropylene. I wish I had the foresight to look closely at where the rest of the rope was when I was pulling it in.. My vague impression was that it was aft of the window, but the whole experience was a bit dreamlike as I pulled it in because I was astonished. The ring or rope didn't make noise on the canopy that I remember.