It may have very long time frames to work in, may be faster or able to evade the nefarious detection intent of humans by working in ways very different from how we work.<p>Read a book recently that contained an interesting AI attack.  Basically, it set a lot of small objects in motion, with complex orbits all computed to result in a large impact at some point in the future.<p>We would not notice something done this way, by analogy.