I’ve always been amazed at how simple rules can create incredibly complex results.  If you’re wondering what I mean, you can try any of the following:

- A small disturbance to traffic flow can lead to a massive traffic jam.  Do it yourself at this online traffic simulator.  If you live in New York you know all about how an illegally parked car can back traffic up for blocks...

- A slight change in demand at a supplier can lead to wild fluctuations in production if there are a lot of middle men (this is why there was so much focus on e-supply chains in the late 1990s).  Look up Jay Forrester’s classic 1958 HBR article “Industrial Dynamics”; here’s another one from MIT Sloan.

- A few simple rules, such as “I want to live next to at least two people of the same race as me” may explain why there are few multicultural neighbourhoods.  See this old Atlantic Monthly article.

For a more stunning visual explanation of this, check out this presentation of Will Wright at Pop!Tech 2006.  He demos his new game Spore (when’s this thing coming out?  I’ve been hearing about it for years...) and shows how by setting a few basic rules, incredibly complex behaviour (i.e., the creation of a universe) can occur.