Some old time programmers could program with just their brains, basically see code, and output working code into a terminal with minimal fixes. This was a must since computers were shared and they were very expensive to use. My feeling is that 10x programmers can do the same. Being able to program in your brain is a huge advantage. I've never worked with one but I have no doubt they exist.

I'm no genius, not even close, but in my math classes, I did so many practice problems related to a subject that after a while I was able to solve some problems in my head without having to write anything down. Super programers aren't necessarily geniuses but they can use their brain to a greater extent before they start programming. I suspect.

I didn't believe it either until I met one. They exist, but it takes more than an interview to gauge and they're so rare it's not worth trying.