Throw a know into a bright green rope. pluck the know from the rope. It visibly changes to a green ball. Press the green ball onto a yellow rope to change it back to a knot – a green knot on a yellow rope! Then the green knot magically changes back to yellow. The yellow knot changes to a yellow ball. The yellow ball is finally pressed onto still another colored rope where it changes back into a yellow knot. Untie this last knot – It leaves a short section of yellow rope in the middle of a completely different color of rope.