This was so much fun! From picking the colors, to working in Illustrator, moving everything about, and creating mockups, I really feel like I learned a lot! Ooh, and way to throw Processing in there too! I didn't actually use it for this but I have before and I'd like to do more with it.
I had a couple variations of this, but the one above was my favorite.
The big tiles are a bit bigger in this one -
I like it but I like the amount of negative space better in the first one.
Here is a mockup of the pattern above but without the smallest specks. In this case, i think the ratios of everything go together well.