A handy little device for making small, flat things — cards, notes, photos, what have you — disappear and re-appear.
The performer opens the door (P in the diagram) and places the card (or whatever) on it and closes the door; covers the device with a cloth; after an appropriate interval and incantation the cloth is removed and the card has vanished! Repeating the process brings it back.
Note that although the diagram doesn't show it very well, the device resembles an ordinary picture frame with glass, with a couple of additions. The door (P in the diagram), which is of light but firm construction, has a light blue lining on the side against the glass; it can be attached by hinges or just fit snugly into the frame. The card is placed on the door, the door is closed, the audience is shown the card THROUGH the glass.
The glass is actually double — two sheets a couple of millimetres apart (V, V in the diagram). In one end of the frame is a small container (R) of very fine blue sand, of the same colour as the lining of the door. When the device is turned upside down the sand pours into the gap, thus covering the card; turning the device again, the sand will pour back into the container.
The whole of the trick, then, consists in the skilful upside-downing of the frame and turning it back.
The sand and lining don't have to be blue but they do have to be of a colour that isn't very bright. It's advisable to have a small and inconspicuous mark somewhere on the back of the frame so that the performer is always sure which way up it is. Spectators can examine the device as long as it's more or less the right way up.
With some patter and several such devices, the performer can make the card move from one to the next and back again: a heightened effect but the repeated turning of the devices, unless very carefully concealed, will arouse suspicion.
Don't let the thing get wet!