When I was a kid, I'm going to guess about 9 years old, I learned to play the soprano recorder. One of the songs we learned was for two recorders, so I recorded one part on an audiocassette (remember those?) and was able to accompany myself. The whole thing was 16 bars, simple quarter- and eighth-notes. I thought I was badass, though in retrospect probably driving family and neighbors nuts.
I know Jacob Collier is ten years older than I was, but still, what kids are doing nowadays (and, in truth, what some very talented kids were doing in my day) is amazing.