s. The boundaries fall into two areas: a 2D vision of a desktop, defined twenty years ago on much more limited hardware, and the relative stagnation of desktop innovation because of, in my humble opinion, a sort of closed fashion of evolution. </p> <p>Recently, there has been tremendous innovation in the 3D capabilities of the personal computer, driven by innovation in games. The idea is not to throw away the existing research in user interfaces developed for the 2D world, but instead to build on it. 3D is 