Bill Box (wood)

The performer displays a small wood box, which appears totally sealed from all sides! A currency bill is borrowed and folded in four, the bill is signed on top. It is placed over the transparent window on top of the box. The box is now tilted away for a moment, then handed the spectator. He is surprised to find the bill sealed inside the box. The spectator cannot open the box. Finally the box is taken by the magician and the bill is removed.