I've tried to find more info on this particular UI pattern Google+ exposes, and I'm sure I've seen it before, but still, I haven't been able to find references to it.
If you go to the Circles section of Google Plus, you will see, besides the circles, a set of "cards" that represent your friends. You can see that all rows are consistent and that if you resize the browser, the cards will rearrange to maximize the use of the space, making the rest fall down to form new dynamic rows.
What is that UI pattern called?