Dolphin bubble rings.
Blowing bubble rings is do-able but not easy, but what dophins can do with them is amzaing, what control!
Dolphins on
youtube1
youtube2
Obviously the dolphins re-energize the bubble rings through the pressure wave in front of their domed skull.
Will try that next time in the pool, although I will have to find something larger than my own skull to produce this pressure wave.
A kid blowing rings in a pool also on youtube
