The game of football (fútbol, soccer) may be the most widely played game in the world.
One player at a time kicks the ball. The field bounds the ball. The referee penalizes players when they commit fouls. A good coach coaches one to many players.
The lifecycle of ball can be modeled by location. The ball is out-of-play before the game begins. At start the ball is center field where it is put in play at the whistle of the referee. The ball is often kicked out out-of-bounds, where it re-enters in play by throw-in. Successful play moves the ball past the facing plane to in goal to score a point. The referee scores the goal and restarts play at center field.