Sneaky Ball

The magician shows a little ball and small transparent box well closed with two elastic bands.  He places the box on the table and puts the ball on top of it, then covers everything with a silk. Now something magical and strange happens, as the audience will see the ball penetrate right through the lid of the closed box.
 
The silk is immediately removed to show that now the ball is really inside the closed box!

• The silk is not included.
• The box misures cm 4×3,5 (1,57×1,37 in.)