Suppose someone gave you a pen - a sealed, solid-colored pen.
You couldn't see how much ink it had. It might run dry after the first few tentative words or last just long enough to create a masterpiece (or several) that would last forever and make a difference in the scheme of things. You don't know before you begin.
Under the rules of the game, you really never know. You have to take a chance! Actually, no rule of the game states you must do anything. Instead of picking up and using the pen, you could leave it on a shelf or in a drawer where it will dry up, unused.
But if you do decide to use it, what would you do with it? How would you play the game?Would you plan and plan before you ever wrote a word? Would your plans be so extensive that you never even got to the writing?