Explanation:

Bitmaps (alt+B) => Creative (V) => Paticles (P) => Style (alt+S) =>
Bubbles (alt+B => Space) =>
Angle (alt+A) 180 =>
Size (alt+Z): 10
Density (alt+D): 5
Coloration (alt+C): 50
Transparency (alt+T):4 => Ok