I've got the Lesson 5 code corrected. I think I'll leave Lesson 05 as is, and make the change I'm thinking of in 06, since it will make texture mapping easier, but doesn't really add much to the Lesson 5 discussion.
I'm a programmer, author, and one of the founders of MartianCraft, a software development shop doing both contract and in-house software development.
My iPhone books (both written with Dave Mark) are published by Apress. My first book, Beginning iPhone Development (currently in its 6th edition) is the all-time best-selling book on learning to program the iPhone and iPad.
I also sculpt and take pictures when I need to engage the other side of my brain a little more.