A Programming Language Embedded in Magic: The Gathering

Previous work demonstrated that the trading card game Magic: The Gathering is Turing complete, by embedding a universal Turing machine inside the game. However, this is extremely hard to program, and known programs are extremely inefficient. We demonstrate techniques for disabling Magic cards except when certain conditions are met, and use them to build a microcontroller with a versatile programming language embedded within a Magic game state. We remove all choices made by players, forcing all player moves except when a program instruction asks a player for input. This demonstrates Magic to be at least as complex as any two-player perfect knowledge game, which we demonstrate by supplying sample programs for Nim and the Collatz conjecture embedded in Magic. As with previous work, our result applies to how real Magic is played, and can be achieved using a tournament-legal deck; but the execution is far faster than previous constructions, generally one cycle of game turns per program instruction.