This is possibly the strongest visible penetration trick, ever invented!
A large wooden square tube is standing on a slightly raised wooden base. The tube has three large holes on the front as well as on the back wall, so that interior of the tube is clearly visible to the audience. Further, on the two side walls, at a distance apart, there are two pairs of slots.
To start, performer places a solid steel plate through each pair of slots, thus blocking the hollow passage within the tube. Next he shows a large die freely, which is found to be a solid one. The die is placed inside the tube, resting on the top steel blade. At the performer's command, the die visibly penetrates the top blade, and now rests on the bottom blade. The entire procedure is repeated, as this time the die visibly penetrates the bottom plate, and drops down onto the base. The tube is removed -- the die and the two steel plates are again shown to be solid.
Magic at its best -- boggles the mind!