Well, most AI techs that exists right now are built upon rules. A very early example may be the chess machine "deep blue", who defeated the world champion Kasparov. A recent one could be Google's virtual brain, who "understood" the concept "cat" by analysing 10 million random frames from YouTube. Another example may be the one S4M mentioned, I'm not familiar with that.

While Google's virtual brain "understood" something, it still doesn't has the ability of analysing. This is an example of unsolved problems.