1.   Steam billowed from under the bonnet.

2.   Mood-setting steam billowed from beneath the curtains surrounding the stage.

3.   Outside the bus, steam billows from two vents sticking out of the rear.

4.   Steam billowed from several pink-yellow, mounded rock cauldrons near and far.

5.   Steam was billowing from between the fenders and hood.

6.   When it is finally unfolded, steam billows forth.

7.   Steam billowed out of the tent into the chilly evening air.