Folding transition effect with tabbar controller

Colin Eberhardt has written a folding paper transition effect, wherein users can interact via swipes (left/right) or a tabbar:

If you watched the WWDC video #228 “Custom Transitions Using View Controllers” you will have seen a demonstration that showed a tabbed interface where you can swipe left and right to navigate, with the view controllers folding like paper. This blog post will show how to replicate this effect.