Mini Metro [$0.99] is a wonderful game, with our very own Mr. Shaun Musgrave giving it a full five stars in his review earlier today. When I first saw it, I thought I was looking at a real metro map (I've had to use trains for many years, so those kinds of diagrams are seared in my memory). That's no accident, apparently, because according to Jarrett Walker, a public transit consultant, Mini Metro is more than just an entertaining game with a metro theme; it's actually a great tool that teaches sound principles of network design that can come in handy to anyone professionally involved in designing city networks. His blog covers how accurate the game is - even though it wasn't designed to really be accurate - and the steps needed to make it more accurate if one was inclined to do so.
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He initially talks about how the demand-generation rules of Mini Metro are on the simplistic side as is the splitting of the city in clear zones (residential, commercial, etc). The other simplification is how these fictional residents just want to go to any triangle, not a specific one; in other words, these residents just want to go to any shopping mall or any home, not necessarily their own. However, these simplifications don't really hurt the game's possible use as a teaching tool according to Walker.
The blog goes on to talk extensively about the differences between how a "real" metro would have to be designed compared to the ones...