I ended up spending way more time on this one than what the authors intended... but came out so much more the wiser. I learned about:
- bitwise operations
- Hilbert space-filling curve
- a neat dictionary mapping bit operation attributed in the comments
- iterating over contiguous elements, very cool (each_cons())
- map and join
- SVG galore
to mention a few. This left me spent, as I'm just sinking my teeth into Ruby but I'm very proud of it. :)