Game using sphere simulating crystal ball - has cards fitting into base which are only visible when viewed through coloured filter in sphere

摘要

The game uses a sphere (11), simulating a crystal ball as used in fortune telling. It has a slot (14) in its base in which a card is inserted. The cards carry information which is illegible in white light and have a motive concealing the information. A lamp (17) illuminates the card which is viewed through a window (13) in the top of the sphere. A coloured filter (22) is fitted in the window, and is chosen to make the information on the card visible when viewed through it. The wavelength of the lamp can be varied instead of using a filter.