A simple tea light holder with a double helix - more pictures at http://happyinmotion.com/?p=1654 and the Fusion 360 design is at http://a360.co/2muvWjz
Best printed in translucent material.
A note on safety - anything with an open flame is dangerous. I've had this printed in PETG for heat resistance. With the tea lights that I've used, the plastic doesn't get hot, but with a larger flame it might. So please use cautiously and do not leave open flames unattended.