The way all organisms depend on the ecosystem for their basic function paints human-made self-replication in a different light. I used to think that we&#x27;ll reach the proper level of nanotech if we learn to make machines that build themselves pretty much from the scratch. Throw a rock in, out swarm of robots go. I used to think that&#x27;s how nature works. That it eats atoms or simple molecules and then spews out organisms.<p>But it turns out, nature is cheating. There are things that human cells can&#x27;t make. We depend on other, smaller organisms to make them. For instance, we can&#x27;t make vitamins ourselves, we need to source them from outside. It turns out that even for replication, cells need to have proper prefabs available in the environment. For instance, we&#x27;re swimming in nitrogen, and plants can&#x27;t use it anyway because it&#x27;s not in a proper form.<p>Which means that if we want to copy this ability, we need to just focus on &quot;vitamins&quot;. That is, all the hard-to-make stuff that requires large-scale, high-tech industry to be produced. If we can tile the area where a robot operates with universal microcontrollers and accept that as a part of its environment, then the problem of self-replication becomes much easier. There&#x27;s a big volcano^H^H^H^H^H^H^Hfactory operating somewhere, pumping out those small prefabs, and robots are &quot;eating&quot; them and incorporating into themselves and their children.<p>Yes, it&#x27;s cheating. But nature cheats too.