I actually had similar theories though in the end I concluded that a person definitely couldn't be doing it, but I did used to rack my brains how the machine did it so fast. I had to do a project on how TV worked and was invented when I was in the 6th grade and it didn't help at all, the whole electron gun thing didn't explain it to me at all because I was imagining the gun like, drawing objects like trees and buildings and people and none of the boring confusing stuff I read helped me understand how this gun knew what to draw and could do it so quickly.