I'm doing a cube-like candle holder. On the bottom, there is a circular opening which can be used to put the candle inside the cube. it's sides have a "maze" like pattern in which the light of the candle, that is placed inside, can escape through. I made the colour of the candle holder white, inside and out, to match the colours of the light flame coming from inside. It's size however, is not too big, therefore very small candles are able to fit in.
RENDERED 3D VIEW
Look in Inventor folder in Design Lab, open candle .IPT file.