There’s an old story about a guy who walked down the street and fell into a giant hole. He yelled for help for a long time, but no one came. Finally he managed to scratch out some notches in the wall, and with some difficulty, he clambered out.

The next day, he walked down the same street and fell into the same hole. He didn’t yell very long before he remembered the notches he had scratched before. He dug them out a little more, and then climbed out much more quickly.