The US patent system is broken anyway, so who cares? It still seems likely that they stole stuff. Google used the same quadtree numbering as Art and Com, that being a coincidence is very unlikely
It's not unlikely at all. We're talking about numbering four tiles in a square, right? There are only two natural ways to do it for anyone who writes in a left-to-right, top-to-bottom language:
1 2
3 4
Or (less likely):
1 3
2 4
In binary, note that both of these patterns naturally assign one bit to left-right, and the other to up-down, which is a very desirable outcome. E.g.: