Here are the famous Borromean Rings. How many linkages are there?
Take any two rings and look at the linkage between them - there are none.
But you cannot pull these rings apart, so they must be linked. How many linkages are there?
For physicists reading this it's an example of a 3-force. Meaning the force between any two object is zero.. until you add a third object.
Content written and posted by Ken Abbott abbottsystems@gmail.com