Andrew Stacey @mathforge.org · Dec 30

This defines a four-component like, in which each pair of components is Hopf-linked. The picture is of the resulting link diagram, and it turns out that it can be three coloured. Look carefully at a single piece of the diagram. It starts at a crossing, where it is an under crossing,

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Andrew Stacey · Dec 30

then passes over the next crossing before ending at the third crossing where it is again an under crossing. Each such piece therefore has for places where it meets other such pieces: at ether end and two in the middle. This is exactly how the module in the origami model works!