Let's look at our first example. An element that flips when we hover over it. I've used hover here to invoke the change as it's simple for the sake of illustration, however the flipping action could just as easily be initiated with a class change (via JavaScript) or when an element received focus.

We will have two of these elements; a horizontal flipping element and a vertical flipping element. You can view the final example at example_08-04. Images fail to fully convey this technique but the idea is that the element flips from the green 'face' to the red 'face' and gives the illusion of doing so through 3D space with the aid of perspective. Here's a grab partway through the transition from green to red which hopefully conveys some of the effect.

Here's the markup for the flipping element...