The cover art is a representation of interpenetrated crystal structures (MOFs). The entangled molecular structures are depicted in gray and red.
The algorithm presented in the paper identifies couples of crystal structures which can be entangled in 3 dimensions. The molecular structures are quite complex and intriguing to explore how these entanglements affect physical properties.
The image depicts three entangled (interpenetrated) MOFs found by the IPMOF algorithm. 18 novel hetero-interpenetrated MOFs were predicted by the algorithm and it would be exciting to see which ones could actually be synthesized.