Why Grandpa can't win at soccer...

Rules for playing soccer with a yoga ball:

1. Zach is always the goalie.
2. If the ball goes over Zach's head - no goal.
3. If the ball hits Zach's head - no goal.
4. Grandpa is allowed only four goals, at Zach's discretion.
5. Goals can be disallowed, at Zach's discretion. This may occur numerous times in the course of a game.
6. The game ends when Zach gets tired.
7. Additional rules may be established during play, at Zach's discretion.
   

Zach, at the game's end: You're old, so you're not a powerful winner.