This is a ball-and-stick model of benzene molecule. As you can see, the carbon atoms (black) are linked using two connections which represent the chemical bonds. It was printed with a gypsum powder printer at the Technical University of Berlin during a summer course.

I designed it like this in order to better represent the ressonance effect and also to make it less fragile since gypsum model this thin will easily break if you're not careful.

The size of atoms and the distance between them take into account chemistry bond theory. The scale is approximately 250.000.000 : 1.