How would Nintendo Fusion work?

[garretslarrity]

So for a few months now we have heard of a rumor that Nintendo's next gen system would be a combination of its handheld and console, Nintendo Fusion.  Many of us here expect it to happen, but I still don't understand how it would work.  So what do you think?  Keep in mind this was never confirmed by Nintendo so please use your imagination to its fullest extent!  Also be as detailed as you can!