It's seem to be a very democratic thinker, but at the same time it doesn't seem to have any reasoning behind the choices it makes. It tries to claim it's using logic, but at the end of the day it's hypotheses are just occam's razor without considering the details of the problem.
A bit, how do you say, disappointing.
Second of all, isn't it ungodly slow? I get that it can draw a few boxes nicely, and maybe shuffle them around, but I had to write my own engine using html canvas because d3 couldn't get svg to flow properly if I had thousands of pixels in my image.
Honestly, if you're going to go through the trouble of understanding d3, I would just write your own javascript canvas to animate things.