A good friend of mine at work shared the video of the Ray Tracer made in Excel. The mad genius. Have a look:
The logic behind that seemed crackers, but there was a link to the book he based it off called the Ray Tracer Challenge. Seemed interesting, a bit much for my non-graphical mind though. I looked at a review that described as a (paraphrased) "stealth way to learn TDD with the Cucumber language". Naturally I bought the book immediately.
I'm up to chapter 5 and hooooo boy am I enjoying it. I've started getting to parts that are getting a bit brain melty for me, which means I'm learning so that's good. But having the code in the book Pseudo-code with Test cases? Magnificent. I thoroughly recommend this book. Friend from paragraph 1 suggested we set this up as a challenge in our weekly skunkworks - everyone pick a language to learn and use the book to learn it. Again, the friend's a genius.
If/when I finish the book, I'll put up a full review but, from up to chapter five, if you love coding and/ or want to explore test driven development, get this book. Now.
Updated: Chapter 6 was TOUGH. Bumped into PHP's copying-objects-by-reference too many times and really scratched my problem solving skills. Hurt, but worth it.