Did You Know You Can Turn Your Magic: The Gathering Cards Into a Turing Machine?
File under: useless but awesome.
A Turing Machine is a simple computer capable of simulating complex logarithms. You might remember the interactive doodle Google did of one a few months back for Alan Turing's 100th birthday. Despite, or rather because of their tremendous simplicity, Turing Machines are able to model a wide range of systems, and in turn you can model a Turing Machine out of virtually anything, from conventional computer hardware to Lego bricks.
Now, smart cookie Alex Churchill has worked out that you can create a functional Turing Machine using only Magic: The Gathering Cards. What?! As Churchill explains,
There's an idea called "Turing completeness", which is used to indicate that a system has a particular degree of complexity. Any Turing-complete system is theoretically able to emulate any other. One way to show that a system is Turing complete is to make a "Turing machine" in it. [...]
But doesn't Magic involve the players making lots of choices?
Normally, yes, it does. But occasionally in normal gameplay you get a sequence of three or four events in a row that are forced to happen by the cards and the rules of the game. The machine below just extends this idea to millions of forced choices in a row.
Churchill has assembled a complete guide for the Magic Turing Machine (...that sounds so disrespectful somehow), including all the cards you need to make your own. Now go forth and compute as Turing intended!