LOVE LOVE LOVE it!
This might help:
http://www.quiltingassistant.com/logcabinblock.html
It has a lot to do with the width of the "logs" in each block but I'd have a dickens of a time figuring out each one on this. Please post more info if you find it.
Then again, it looks a bit like each block is a "mini bargello" and the block that butts up to it is coordinated to create the flow of color. Just a guess.