Jumping Silk on Knot

This is similar to the popular Monkey Bar effect, with a silk knotted on a rope jumping from one end to the other, then to the middle. The prop makes a big display for larger audiences, but can be carried in your pocket. And though mechanical in working, everything will stand examination at the finish !
Effect :- The performer displays a length of red rope, with three yellow knots. Tied in the knot to the right is a silk.
The rope is passed behind the performer’s back and the silk has jumped to the knot to the left. It goes behind the back once again, and the silk has jumped back to the knot on the right.
You milk this for what it is worth, as the audience tell you you are simply transferring the rope from hand to hand, so that the silk appears at opposite ends.
You appear offended at the suggestion that you are cheating so brazenly. You pass the rope behind your back once again, and this time the silk has jumped to the knot in the middle.
And you can immediately toss everything to the audience, and they can examine the rope, silk and knots without a clue to the magic.
The apparatus supplied includes the special knitted rope, silk, and full instructions.