A mirror will not show you yourself, if you do not wish to see.
—ROGER ZELAZNY, LORD OF LIGHT
After you have a vague hand-wavy understanding of what you plan on building, the next step is to create a prototype. A prototype is a quickly assembled sketch of a game. “Quickly assembled,” however, is relative. For a game that will be made over the course of years, a prototype may take months to build. For a small card game, a prototype can be assembled in minutes. Prototypes are the single most useful tool for game designers for many reasons:
• Prototypes force the designer to make decisions about non-obvious edge cases.
• Prototypes focus on the core idea without the designer having to spend time on expensive polish ...