The Verge Changing/flowing Article Design Layout type?

Hi Guys:

I don't remember which article it was...but I remember reading an article one time on the Verge...which had just an absolutely beautiful background layout. Essentially.. as you scrolled down the page, the background would change, with the text still overlayed on it nicely.

Can anyone link me back to the article that was done? Or alternatively explain to me how this dynamic flowing background words?