Paul Eremenko, the head of Project Ara showed the prototype of Project Ara at Google I/O 2014.
Though the phone failed to fully load, Audience cheered on seeing the Android bootup screen.

Project Ara is the codename for an initiative by Google that aims to develop a free, open hardware platform for creating highly modular smartphones.
https://www.youtube.com/watch?v=0He3Jr-fZh0&list=PLK2ccNIJVPpBKf0ko0817k_fjKZzWwcQW

3-D printing is great, assuming you're printing one material for one purpose, and that you're fine with a few do-overs. But the technology is still far behind in reliably producing a variety of useful objects, with no assembly required, at a moderate cost.
https://www.youtube.com/watch?v=xxdnFjfMiik&list=PLK2ccNIJVPpB_XqWWq_oaZGIDzmKiSkYc