This is a scanning transmission electron microscope image of a fullerene layer between two graphene sheets. Due to the motion of the fullerenes at the edge, they are only partially visible.

The samples consisted of alternating layers ... fullerenes tailored for specific applications, such as for storing hydrogen in fuel cells. Individual sheets of carbon atoms, called graphene ...

Stacked on top of each other make graphite (1 mm thick graphite contains about 3 million layers of graphene); rolled up make a carbon nanotube; cut and folded into a spherical shape make a fullerene.