The magician shows the audience two pillars with cords running between them at both ends. The drawing which is included here makes this clear. A spectator is given the choice of which cord they would like to see cut. The pillars are placed together and the magician cuts through the selected cord. The spectators see that the cord really is cut, yet when the pillars are placed together again the magician pulls the cord backwards and forwards proving that it is magically restored. Complete with instructions.