I was severely confounded by this effect and I would like to practice and rehearse it myself. I will describe it as I saw and remember it, hopefully someone will let me know a source for this effect.
The magician cuts a long length of string from a spool, probably 5-6 feet. He then asks the spectator to inspect the string. The magician then props up a hard cover book standing on end in a "V" fashion so that the inside of the book is toward the performer and the cover is toward the audience; this forms an impromptu screen. He then takes the string and places both ends over the top of the propped up book and places them both on the audience side then winds the middle portion of the string on the performer side of the impromptu screen. He then asks the spectator to look at the performer side of the screen and see that the middle of the string is intact. At this time, the performer asks to borrow the spectator's finger ring. The magician takes the ring behind the impromptu screen, out of site, and makes some movements. The magician then reaches over the impromptu screen and takes the ends of the string that were left in full view the whole time and still lying on the audience side and starts pulling the slack out of the string toward the audience until the middle of the sting finally emerges with the borrowed spectator's ring magically threaded on the string.
Does anyone have any idea what effect this might be and perhaps where to find it?
Thanks for any help on this.