The Copylight lamp is an ordinary light-bulb lamp, where the bulb is situated behind a semi-opaque white plate. The plate is covered by a clear plastic, where you can put a film sheet of your choice to display. The front is 30 x 30 cm, and an A3 sheet will fit as the short side of the A3 is 30 cm. Copylight has a lot of ready-made designs available to purchase, but it's funnier to make your own design to display. The copylight is rather expensive (Around 100 USD), especially when considering how little materials that went into this design. It's very fun to have, never the less. Since they are not too big, it's easy to make a matrix of them in a square meter with nine motives. For example a pac-man figure or something like that. My Copylight has a CLC print of Lain at the moment.

Schematic:

Opaque back       ->||
                _   || --Clear plastic front
Lightbulb  ->  / \  ||
               \ /  ||
               | |  || 
Wall mount ->|------||
               |    
               |  --On / off switch (Cord-operated)
               |
               |
               o

For a good look at how this works out, visit this adress:
http://www.lichtgalerie-mn.de/lbrainb.htm
(Not a commercial site.)