Knockdown It is a metaphor for the setbacks in life and sports and the ability to get up and start again, even if we make the same mistakes. Boxing has been used as a metaphor for the struggles in life by many artists. Sport offers a way of managing aggression. I am a keen tennis player and like so many sports, without some aggression, it's hard to play the game or watch. The wilder, more dynamic paint lines represent that passion.