Please explain the architectural term "floating cloud effect"

When reading about the Sydney Opera House I keep coming across the term “floating cloud effect” but cannot find any definition of it. What does it actually look like? I’d appreciate some links to pictures. I look forward to your feedback.

From this text and the night time pic of the Opera house included in the article it appears to reference design choices that make the upper part of of the building seem in some small way to be free floating.

Thanks Naita. It’s strange that there doesn’t seem to be a proper definition of the phrase “floating cloud effect”, even though it’s used quite frequently.

If you look at the building, I think it’s possible to divine the meaning of the term. The white shells are larger at the top than the bottom, and the supports connecting them with the ground are narrow and inconspicuous. It looks like it isn’t supported.

Thanks Mangetout. You nailed it!