iPad Apps featured on Apple.com

In the hero spot for iPad on Apple.com there are two apps. One is letterpress, but I can't figure out what the other one. It is showing pictures of Kevin Will Chen (who is the art director for Apple).

You can also see it here: http://www.apple.com/ipad/why-ipad-retina/

And then on that page there is also an app featuring Rio De Janeiro. What is that app?

Thanks

yes, that was the delta app. Still no word on that photo app though. Weird that it is so hard to find out. I'd think Apple would want to say what it is, or at least someone on these forums would readily recognize it.