Some theorists worry that in the not-so-distant future, self-replicating machines will continue to reproduce until the entire world is overrun by machines. While this makes for a great addition to “The Matrix” trilogy, it’s probably not going to happen in our lifetime. If there were anything to worry about though, RepRap would be it.
RepRap is a rapid-prototyping machine that allows for the 3-D printing of objects. As of writing, it can currently reproduce every piece of itself, including its brain. Now keep in mind, it needs plastic to build parts, so with that said, I think we’re going to be OK.