"It should be pointed out, however, that physics is not the only systemic toy upon which fun games can be built. Probability fields, such as those forged by the colours, numbers and suits in a deck of cards, and the stochastic patterns that emerge from mixing those cards up, are another well-known toy upon which many great games are built. In fact, there is a literal infinity of foundational systemic toys upon which meaningful games can be built, yet for the most part, the game industry focuses on building baseline game engines that simulate one single toy that is proven to only be marginally fun: physical reality."