Nothing, just some R&D into optimizing 3D structures, like what was done with 2D. 3D chips have been an obvious step forward since the first 2D wafer, it just h

Nothing, just some R&D into optimizing 3D structures, like what was done with 2D. 3D chips have been an obvious step forward since the first 2D wafer, it just happened that making stuff smaller was easier, faster, and as long as Moore's law held true, also good enough. Now that we're reaching its limits in pure 2D, comes the time to go full 3D... and DARPA wants to be the first one.