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This project builds on Motion. I've added the ability to place magnets on the field.
This is a work in progress. There are a few bugs, the magnets aren't quit right and it can be a real compute hog when the number of magnets exceeds three or so.
However I think this is a good example of what Logo can do.
When placing magnets on the field there are a few rules that seem to give the most interesting results. First keep the number of turtles below three, second keep the speed of the turtles low. When placing magnets try to keep close clusters of magnets below three per cluster.
Here are a couple of things you can try: