Krzysztof Zabłocki on the Cocos 2D blog with an interesting article on not including a "brush size" tool in Foldify. The end result is an extremely effective way to effectively change brush size by zooming and avoiding problems like having a brush which is smaller than the user's finger. For me, Foldify was easily my favourite app of last year and I am very pleased to see it getting so much coverage.
Interesting discussion by Max Rudberg on guided walkthrough screens in iOS apps with responses/updates at the bottom by Phil Ryu of Clear. I am also not a huge fan of this style of walkthrough but appreciate that this is an extremely hard problem to solve for apps with very minimal UI.
Beautiful Pixels has been doing a best of 2012 series over the last weeks or so and for me this was the most interesting post of them so far. Unsurprisingly, Letterpress makes the list which is good to see as it is pretty much a masterclass in beautiful UI interactions. Also interesting to see a Google iOS app make this list, I'm not sure that would have happened a couple of years ago.