![](https://www.ch.ic.ac.uk/rzepa/blog/wp-content/uploads/2019/12/trefoils-1024x492.jpg)
Here is another molecule of the year, on a topic close to my heart, the catenane systems 1 and the trefoil knot 2 [cite]10.1126/science.aav5021[/cite] Such topology is closely inter-twinned with three dimensions (literally) and I always find that the flat pages of a journal are simply insufficient to do them justice. So I set about finding the 3D coordinates.