Coverflow like animating grids or contentcontrol

Hi,

That's really frustrating, some days ago I felt on a tutorial page on how to animate grids (or contentcontrol...I don't remember).
...and now that I need this page I can't find it again ;-)
There was an illustration like this (light blue squares)

The principle being to animate scale in/out for centered object and opacity in/out for first and last object

Would you by chance see the page I'm referring to? (or at least lead me to a similar article!)

Thanks a lot!!