Changed the light bulbs on this 50s lamp the other day – from opaque to clear (wherever they came from!). And lo-and-behold, a wonderful pattern showed up on the walls. Must have been the designer’s original idea all along? Great one!
BTW – Norwegian design, I think.
(annspun) 
WOW, how cool is that? Love the patterns and light in the picture. Good job 🙂