[JohnDotAwesome]

I used to notice something similar in college.

cough We were smoking a lot of... various things. I had setup a chill room that didn't have any air conditioning (so it was actually very hot; a hot box if you will). Just a small room where smoke would accumulate.

At any rate, I got very good at blowing smoke rings. In the still room, you could blow a smoke ring and it would expand for about a minute before dissipating. The more substantial rings would do something really crazy. They'd spawn a new, smaller ring, but going the opposite direction. I believe this was only the case if the ring was blown upward.

I don't know if this is related to the Two Vortex Ring Collision experiment, but it was definitely fun to watch!

[tlarkworthy]

Vaping and youtube has taken smoke ring blowing to new level https://youtu.be/zVXR7xttUeo

[TheSpiceIsLife]

I don't see any reason why this shouldn't be an Olympic sport.