Three rings {Borromean rings} can overlap, so that no pair of rings has a link but just overlaps, but the three rings cannot separate because each third ring passes through overlapped region of the other two.
A ring can pass through another ring so the rings cannot separate {link}.
Twist one ring to make loop and pass ring through loop {trefoil knot}.
Twist one ring to make two loops and pass other ring through the loops so the rings cannot separate {Whitehead link}. The rings have no net linking.
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Date Modified: 2022.0225