Critically, the helium atoms are seen to work in pairs - just as in superconductivity, electrons work in tandem.

BBC: Magnet repelled over superconductor, SPL

Why, then, are some chief executives still being asked to work in pairs?

ECONOMIST: Schumpeter

Students may work in groups or pairs.

CNN: Lesson Plan: Proms for ill teens

We have six, who work in three partnered leadership pairs.

FORBES: It's Time to Abolish Bosses

The Superintendents' Association, which represents senior officers below the rank of chief constable, argues that officers could patrol alone, rather than in pairs, and detectives could work in uniform, rather than in plain clothes.

ECONOMIST: Jack Straw takes on the law

Not all secure high-flying jobs: many come to study, or to work as au pairs or waiters while perfecting their English, or to find a niche in London's huge creative industries.

ECONOMIST: The French community in London