Opening door effect using Core Animation

I'm trying to create a transition/animation on a UIView that looks something like the image in the link below. It would start with a UIView that is a standard rectangle shape, the view would then animate/transition like the left side is being pushed and it rotates on the right side corner, like a door opening slightly. I'm sure this is a really easy thing to do in Core Animation, and I've tried searching for solutions, but haven't found any examples.

Here's an example of what I am trying to achieve: