And we had never landed - soft-landed an object on the surface of Mars, and there was no textbook.

NPR: Revisiting the Viking Missions to Mars

"How the sound reflects off this reflecting surface with this composite object on it - which is pretty big and has a cloaking shell on it - really reflects... just like a flat surface does, " Dr Cummer said.

BBC: Acoustic 'cloaking device' shields objects from sound

Electrostatic self-assembly, however, coats every exposed surface of an object, and does it at room temperature.

ECONOMIST: MONITOR

In this example, the surface is not simply connected and any smoothed-out object looks like a torus with at least one hole.

ECONOMIST: Proof of the truth of the Poincar�� conjecture

Previous studies of Trois Hommes Armes de Lances had used X-ray fluorescence - which yields a list of all the atoms within an object - but showed that there were atoms present in the work that were not present on the surface.

BBC: Terahertz scanner reveals hidden fresco at Louvre