You’ve got this wall that you’d like covered in mud. You can go into your garden and make a bit of mud. Then you can throw it at the wall, and some of it will stick. If you’re lucky, you’ve got a big enough garden, so you can make enough mud to cover the entire wall. Unfortunately, once the wall is covered in mud, you realize that the wall is much bigger than you thought it was, so there’s lots of it not covered by mud. But that’s ok, because people liked the mud you threw earlier, so they’ve given you the resources to build a mud factory, and now you can afford to throw as much mud at the wall as you like. It doesn’t even matter how much of it sticks, because there’s always more mud, and there’s always more wall.