In Dungeons & Dragons, a character can change as play goes on – Ewalt gives the example of the wizard character played by one of his friends, Brandon, who got better at his skills over time and can now create huge fireballs. When Brandon began the game with the character, he couldn't perform any spells at all. "Characters don't just persist from session to session, they learn from their experiences," Ewalt writes. "Anyone who has played a video game in the last twenty years won't find that shocking. But D&D pioneered the idea of characters that become more powerful over time; before its invention, games were almost all static. The rules of Monopoly never change, no matter how many times you go around the board."