You show a small black bag with three ends of colored ropes hanging out of it, a red, yellow and blue rope.
THe spectator can choose any of these ropes (freely name one), let’s say the yellow rope. You pull out the yellow rope out of the bag and hand it to the spectator (or the spectator can do it himself), nothing special so far. But then you tell him he has choosen the only rope that is special because it doesn’t have a knot in it. Now take the other two ropes out of the bag and these both have knots in them.
Take out the knots and hand everything out for examination, there is nothing to be found. You only use the three regular ropes and the bag, no sliding knots!
We supply the three ropes, bag and video-instructions. Very easy to do!