Harvest enough of these, and arrange them in the right order, and it is possible to knock together a piece of software that can perform any task you like.

ECONOMIST: Computer viruses

In the long run over-investment and a collapse of the profits might knock heads together.

ECONOMIST: Making cars in Latin America

But he said he was hopeful Ms Barnes could "knock heads together" in order to get the police and NHS to work together to provide better facilities for rape and sexual assault victims.

BBC: PPC Ann Barnes in rape victim centre pledge

The Transport Committee has its last session on the traffic management inquiry (how do you knock utility company heads together to limit holes in the road and curb congestion without road pricing etc...).

BBC: Viewing guide: What's on in Parliament in coming week

Mrs Clinton also wants to knock opposition and government heads together, to reach a modicum of unity over the war against the Taliban and relations with America.

ECONOMIST: Clinton flies into a war zone

Taken together, the reforms promise to knock Germany's Misery Index figure from 143% to under 124% --a huge competitive boost.

FORBES: Mind the Geese

Now, on the other hand, when business and labor are working together, then we can compete against anybody, and we can knock down trade barriers in other countries, and we can start selling products around the world.

WHITEHOUSE: Making the Right Choice for the Economy