This is Rechner, a new app for iOS. It's a calculator, but not an ordinary one. For one, it's prettier and much simpler. But, most importantly, it's fully gestural, designed for a touchscreen. According to its creators, it's 200% more efficient than a regular calculator.
Basically, they created four basic gestures of additions, subtractions, equal and clear, which they think are the more commonly used functions by normal people. They hid the rest of the calculator functions in an easily accesible drawer.
I guess that, if you only use basic function, it can be faster to use once you learn the gestures. I'm having a hard time to believe it, so we will have to try it when it comes out "soon." [Rechner via Necedades—In Spanish]