BOTH SIDES of the frame are mirrors, you can show it to the audience from both sides at ANY TIME. The magician takes a silk and starts rubbing the middle of the mirror.
Believe it or not, the silk pierces the mirror.
It can be seen very well on both sides.
You can push the silk in or pull it out.
When the silk is removed, the audience can see that there is NO hole in the mirror which the spectators can examine from either side.
A SUPERB IDEA + IMPECCABLE QUALITY = A STUNNING STAGE EFFECT!