Six years ago, I saw some source code that has stayed with me ever since. It was a piece of Erlang code that described the game of Texas Hold'em poker. What struck me was the beautiful simplicity in that it described exactly the rules of poker and nothing else. This was very different from the legacy poker system I wrestled with at the time. I decided then and there to set a goal to create "a card rules engine". I even added this goal to a website which kept sending me emails nagging about this goal.