Magic the gathering is Turing-complete

I just mentioned Conway's Game of Life as an example of a Turing-complete system.

Though it's called the "Game" of Life, and some people describe it as a zero-player game, it's not really a game in the traditional sense of the word.

For an unexpected example of an unambiguous game which is also Turing-complete, check out Magic: The Gathering. It has been shown that a Universal Turing machine can be constructed inside Magic, and hence that it is Turing-complete.

I played a lot of Magic in high school, though it's too expensive of a habit to keep up for long. If, like me, you remember Magic fondly, but don't play it so much any more, might I recommend Mark Rosewater's Drive to Work podcast?

Life in Life

Conway's Game of Life is a well-known cellular automaton in which, every tick, the state of each of the cells on a giant grid is determined only by the states of its immediate neighbours in the previous tick. Despite its extremely simple definition, it is famously Turing-complete, which is roughly to say that it can compute any computable function.

And so, of course, someone has written a Life emulator, in Life.

Perhaps it's Life all the way down...

(Not) the future of interaction design

This is kinda old, I think, but it's pretty great. A rant by Bret Victor on the Future of Interaction Design.

From the rant:

... There's a reason that our fingertips have some of the densest areas of nerve endings on the body. This is how we experience the world close-up. This is how our tools talk to us. The sense of touch is essential to everything that humans have called "work" for millions of years.

Now, take out your favorite Magical And Revolutionary Technology Device. Use it for a bit.

What did you feel? Did it feel glassy? Did it have no connection whatsoever with the task you were performing? ...

Moving pictures under glass

Go read the rest!

Goods and services

Read this old, unsurprising report in New Scientist. From the article:

Automated trading ...has come to account for more than half of trades in many markets around the globe. ...Because of the finite speed of light, trading speed depends on where you are sitting. ..."The basic insight," says Wissner-Gross, "is that the optimal location lets the trader exploit fluctuations equally on both exchanges." ..."This shows that the technological arms race to extract every penny from high-frequency mechanical arbitrage will soon reach its ultimate limits," says physicist and hedge-fund manager Jean-Philippe Bouchaud

If this is how money and the free markets work now, I'm pretty sure we no longer know what words mean.