The easier analogy is literally anything that exists.
If it is already within human limits, learning how to do it is merely an act of patience and study. In past times, people understood this far better. There's a reason why so little practical knowledge is put to paper and was only passed on via apprenticing. Most skills are not hard to copy once you know the core tricks to them. Even modern corporations guard their secrets incredibly closely. Most shit is fairly simple once someone actually managed to figure it out the first time. You know you can build a working nuclear reactor in your back yard? A primitive one, but it works just the same. Some kid did that and created a huge fucking problem. The government is scared shitless normies will catch on that most things are not that difficult and start doing insane shit in their own home like this.