tricks Ping - though pin

effect: you separate two linked safety pins without opening them -proof that solid can penetrate solid.
Secret: link two large sofety pins together. Hold them as shown. Pull them apart with a sharp downward movement on the right hand pin.
There is a knock to getting this movement exactly right but with practice you will be able to do it every actually happens is that the pin on the right opens the left pin for a moment. The left pin closes again and it appears that you have coused metal to penetrate metal.