As a fan of geometry, and especially stellations (see the logo in the upper left), I have mixed feelings about the 3D star light fixtures I often see. They are pleasing, but they are not based on any real math. They look like stellations, but they are not. Susan will point out a star lamp to me, and is used to me replying, "It's nice, but it isn't right."
Hans Schepker to the rescue! His mathematically correct lighting page demonstrates that you can make light fixtures based on strict mathematical forms. He has some really interesting compound form lamps. The three cubes compound is especially nice:
You may recognize the shape from the top of one of the towers in Escher's Waterfall.