This one actually isn't Mike Bostock. It's just "hosted" via his `bl.ocks.org` service. The code itself lives in a Gist[0].

The original author is blacki[1][2].

[0] https://gist.github.com/blacki/ebba08223eba20b56b62 [1] http://bl.ocks.org/blacki [2] https://github.com/blacki