Thank you for your votes and comments !
I wanted it as abstract as possible, even if it makes it different from what is usually done in this type of challenges.
I'm glad it received an average higher than 5 : )
That's a cool shot! I don't really know what it is, so maybe another element would help us to understand it... for example, if it's a really small bubble, have the point of a needle poking at it or something :)