The CSS hummingbird is cool. It shows off the awesome ability of the software professional to take a half dozen stupid, illogical constraints and somehow end up with something that works anyway. The problem is that companies would not need to select for this quality if they could avoid imposing stupid, illogical constraints in the first place.
So the obvious followup question I would ask first would have been, "Why did you choose to do this with CSS rather than with a language designed for vector graphics, like SVG?"
Shall we also hire all the other people who can make their cats bark and their dogs meow?
I don't think making cats bark would be very relevant to an Internet technology company, but it would probably be a good sign in a relevant industry (say, a company that trains animals).
That's the point. This person did a neat little project that uses skills which are directly relevant to the job being applied for. The project probably isn't actually useful on its own, but it shows interest and ability.
I also thought about this as well. At first I even thought it was an SVG image. Don't get me wrong, it's pretty damn awesome that he was able to use CSS transforms to create that but...why? I guess it shows how to think critically and maybe he did it in CSS because it's backwards compatible. I don't know. I don't know the backwards compatibility of CSS transforms vs. SVG.
So the obvious followup question I would ask first would have been, "Why did you choose to do this with CSS rather than with a language designed for vector graphics, like SVG?"
Shall we also hire all the other people who can make their cats bark and their dogs meow?