Where is Graphic Design?

Above are a small selection of portable, yet heavyweight 'speech bubbles' that were placed all over a Barcelona beach recently. I think the idea is incredibly clever and striking. The use of such bold, simplistic graphic designs reinforces the message the organisation was trying to communicate; clean up your rubbish. Speech bubbles were in both Spanish and English, yet even if I was to look at one in Spanish I would be drawn in and would want to investigate as to what its translation was.