The basic idea of the City Traveler is to create cities and allow travelers to move between them. Each traveler that makes the journey leaves behind exactly one pixel.
The images below are composed of 144 cities with 5000 travelers making a total of 2,500,000 million journeys.
What is unusual about City Traveler is that the cities are allowed to move.
Cities move according to a simple set of attraction rules based on the locations of other cities and the travelers visiting from those cities.
Strange loops of attraction are often created. Feedback drives continual movement

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1003 In this image there are only 25 cities.