核心畫面

You can picture a ruler with a short band marked on it. Someone else paints the band and you never touch it. All you do is say the real number will land past the right-hand end of the band, or short of the left-hand end. Then the ruler decides the money: every extra step the real number lands away from the band moves the amount again, in your favour or against you. Nothing about this picture says who won the game or who owns the shares. The whole thing is about a number and a band on a line.