https://www.youtube.com/embed/6DaAjyPOInQ

Any video game sets limits to what a player can do, and those limits change the way the player behaves. The game rewrites the rule book for real life.

The same thing happens to parents of children with cancer. "All the tricks you learn as a father to comfort your child don't work," said Ryan Green, whose five-year-old son Joel died of cancer in 2014.

Green shared his story on stage at the 2016 WIRED Business Conference today. Green described how his son's illness inspired him to build a video game, That Dragon, Cancer, to help others understand what his family was going through.

The game explores, as Green put it, what you do in life when the level is broken, when you can’t get to the goal no matter what you do. The goal of the game is not to win or get to the next level, but to find the moments of grace in the darkest of times. "You just need to make Joel laugh," Green said. "That's all you need to do."

To learn more about Green, his son, and That Dragon, Cancer, see

"A Father, a Dying Son, and the Quest to Make the Most Profound Videogame Ever" by WIRED editor-at-large Jason Tanz.