If I didn’t mention it before, your light source can be varied including anything you might have at hand, candle? Flashlight? Cell phone even. This image was created with a small flashlight simply moving back and forth across subject during a long exposure. Allowing beam to stay in one spot of course brightens the area exposed. Less and darker. The pattern is up to the artist. Go do some light painting! A soft focus filter adds to the effect and emulates the look of the Hose Master technique brought to my attention by Scott Blaylock of Digital Arts and Graphics.