One of the nice and less common effect we see in light painting is smoke effect. Despite of its relative rareness it is requite easy to make as light painter Wen-Jié Yang demonstrates in the video below.
As always with Wen-Jie, this is a fast paced, French speaking clip, but well worth going through the subtitles..
Two quick comments:
1. What Wen-Jie refers to as Neon-Flexible (which is actually the smoke making wonder) is sometimes knows in more “American” English as EL-Wire, so if you are looking in amazon or other on line US stores try looking for EL-Wire.