The point is that you can never ever run out of things to write about. Just let your hand go, and it will write something. If you put no blocker on it, no filter, and you have no criteria, and just write whatever is flying through your brain down on a piece of paper, or a wall, or a table, or whatever it is you’re writing on, you can’t possibly run out of things to write because your brain is always firing, there’s always something shooting through it, every fleeting moment from its formation until your death — your brain-death, that is. If your heart is beating but your brain is blank, you aren’t really alive, because you can’t write anymore. At that point, you have truly run out of ideas.