It's always fascinating that with smoke you will NEVER re-create the same shot twice... and you cannot predict what will happen. The slightest air movement changes the dynamics.
Try this... in a darkened room point a lazer pointer straight up over the smoke and watch the effect... with the smoke under the pointer (the smaller the better-- i.e. a keychain type) and letting the smoke build up around the beam... experiment and I think you'll see what I mean.
I use those cone type incense burners.
Lemme know how you like it. And post the results. :uhyeah:Darn it...Now I gotta do this tonight! LOL